Mk4-R Challenge Car Kit: $21,990

The Challenge car is a fairly heavily modified roadster kit, designed for wheel-to-wheel professional and amateur racing. The big differences between the competition focused Challenge kit and the roadster kit are listed below, but many of the parts are identical.

What You Get


Modified Mk4 chassis with full competition cage (NASA and SCCA legal), front and rear tubular additions, and side impact tubing. Includes mounts ready to accept a wide variety of engines/transmissions/suspensions.

  White powdercoating optional


Hand laid 3/16” laminate composite body and panels made with vinylester resin. Slots cut in body for cage.

  Driver and passenger doors without molded door liners and non-functional hinges
  Hood with molded hood liner, separate hood scoop, and hood pins (hood hinge not available)
  Trunk with molded trunk liner
  Includes secondary body fasteners
  Adhesive backed and foam weatherstrip, C-channel door edge trim, and fasteners
  Carbon fiber rear body covers
  Plastic end caps and body fasteners
  Trunk and engine bay seal, push on rubber bulb seal
  Rubber hood and trunk bumpers
  Includes adjustable hidden trunk hinge kit, hinge mount plates and fasteners
  Original quick-jack comp bumpers with stainless steel sleeves and fasteners

Chassis Aluminum Panels:

Includes 54 laser cut, pre-formed 6061-T6 aluminum panels for cock pit, trunk, and engine bay.

• 1,200 pre-packaged rivets; 1/8” and 3/16” short and long
  Complete MK4 cockpit aluminum with optional block-off plates and covers
  Engine bay aluminum assembly with aluminum nose sections and splash guards

Complete Front Suspension:

Unequal length A-arm control arms with coil-over shock suspension. Comes complete with all components and fasteners.

  KONI brand high-performance mono-tube, rod-end shock absorbers
  Coil-over kit for KONI dampers including spring hat, threaded seat and 750 lb. black powdercoated Competition springs
  Adjustable upper control arms with ball joints and fasteners
  Lower tubular control arms with ball joints and fasteners
  Forged steel spindles with integral upper ball joint mount and fasteners
  Competition front sway bar
  Competition adjustable bump steer kit

Rear Suspension:

  FFR Deluxe 3-Link suspension kit with rear-end brackets, upper link kit, and fasteners, including panhard bar kit with rod-ends and grade 8 fasteners
  KONI brand high performance mono-tube, rod-end shock absorbers
  Coil-over kit for KONI dampers including spring hat, threaded seat and 500 lb. black powdercoated Competition springs
  Factory Five forged rear lower control arms with polyurethane bushings and fasteners

Brake Kit:

  Front hubs, fasteners and dust covers
  Front brakes, Ford Mustang GT 11” front rotors with twin piston PBR aluminum calipers, brake pads and fasteners
  Master cylinders (listed in pedal box assembly), stainless braided brake lines front with mount clips, banjo bolts and brake line mounting fasteners
  Pre-flared 3/16” brake line and brake line T-adapter
  Complete emergency brake handle assembly with leather boot and fasteners

Complete Steering System:

Complete steering system using 15:1 power rack from tie rod ends and fasteners to vintage steering wheel and badges; collapsible design.

  15:1 power steering rack with tie rod ends, hoses, and fasteners
  Polyurethane steering rack bushings and fasteners
  Rack shaft adapter 9/16-26 spline
  Nickel plated lower steering shaft (fully welded U-joints)
  Collapsible upper steering shaft, with friction washers
  14” Competition steering wheel, black leather and aluminum with boss and FFR center section and fasteners
  Steering bearings and hardware, including flange bearing, pillow block bearing and fasteners

Complete Fuel System/Parts:

Based on OEM style fuel tank and
system, this assembly provides everything from the gas cap to the lines, and is designed to work with carbureted or fuel injected systems.

  OEM style fuel tank with mounting straps and hardware, vents, gaskets, pick-up and fuel level sending unit
  Fuel lines, connectors, and filler neck
  Pre-flared fuel lines (1/4” and 5/16”) with unions, barbs, hose clamps and high-press flex lines and fasteners
  Aston LeMans style polished aluminum fuel cap with integral pressure cap, gaskets, ground strap, fuel hose to tank with fasteners
  3/8” line, fuel filter, and connectors
  Optional race fuel cell cage

Complete Cooling System/Parts:

Electric cooling fan and mounting hardware, radiator hoses, and

  Electric cooling fan and mounting kit
  Aluminum radiator with cap and in-line filler neck
  Radiator mount kit and fasteners
  Stainless steel radiator hose kit including adapter kit, fasteners and hose
  Stainless overflow tank with cap, hoses, hose clamps and mounting hardware
  180 degree thermostat switch and wiring

Engine Accessories/Side Exhaust:

The Mk4 completed kit is configured to accommodate the 5.0L, 4.6L, 5.0L Coyote, and 390/427 engines with exhaust options to use many other engines. Kit comes with alternate drive pulley assembly, oil filter relocate kit, and exhaust assembly to adapt
Mustang engine and headers to vintage side exit exhausts.

  4-into-1 side exhaust, bare steel with rubber hanger brackets, gaskets and fasteners
  1987-1995, 1996-2004, or Coyote straight pipes
  J-pipe header-to-side exhaust adapter, optional catalytic converter replaces this part.  Full tubular headers are also an available option
  Oil filter relocate mount with fittings, hoses, barbs and fasteners
  Spin-on engine block adapter
  Alternate drive pulley, spacer, pulley wheel and fasteners
  SB performance air filter, conical
  A/C replacement pulley kit and custom length fan belt with fasteners.
  Optional full length tubular headers for: 302, 351, 390/427, and Coyote
  Optional catalytic converters for: ‘87-’95 302, ‘96-’04 4.6L
  Optional shorty headers with J-pipes for: 5.0L Coyote
  Driveshaft: Select from one of six available driveshafts with fasteners to match the engine/trans, and rear end of your choice. Some of the available driveshafts:
- 28 spline 10.375” driveshaft for T-5 or Tremec 3550s
- 31 spline 10.375” driveshaft for Tremec TKO 500s or 600s
- 31 spline 12.875” driveshaft for 4.6L engines with T-45s or 3650s

Gauges, Dash, and Electrical Assembly:

End those wiring harness woes. Integrated harness and electronic gauges are just the start of this massive assembly. Choose either vintage/replica or modern/performance gauges to complement an authentic street style dash. Complete assembly comes with covered aluminum dash, dash buttons, toggles and indicator lights, switches, and horn.

  MK4 pre-cut aluminum dashboard with fasteners
  Padded dash cover, black vinyl
  Custom fit chassis wiring harness, wiring harness mounting kit, and hardware includes fuse panel mount
  Ignition switch with FFR keys, headlight switch, three-position turn signal switch, starter solenoid and horns.
  Red, green, and blue dash lights
  Insulated line clip hardware and fasteners
  Cable ties, wire loom and flex grommeting
  On/off switch, horn button, flasher and all connectors
  Battery ground strap and competition battery cut-off switch
  Trunk mount battery hardware, cables and hold-downs with fasteners
  Speedometer sending unit, pigtail, fasteners and 3.55 speedometer gear
  Complete set of seven Autometer electronic gauges, with connectors, terminals and installation kit, which includes the following gauges:

- Speedometer (programmable)
- Tachometer
Oil Pressure Gauge
- Water Temperature Gauge
- Fuel Level Gauge
- Voltmeter
- Oil Temperature Gauge

OR select optional complete set of seven vintage FFR replica electronic gauges with connectors, terminals and installation kit, which includes:

- GPS Speedometer (reverse read)
- Tachometer
- Oil Pressure Gauge
- Water Temperature Gauge
- Fuel Level Gauge
- Voltmeter
- Clock

Interior Accessories:

The MK4-R Challenge kit comes with
the competition interior accessories you need. Race seat, toggles, rear view mirror, and more complement the dash and gauges assembly. Customer must add fire supresion system. Check out this full list of standard parts and assemblies.

  Competition high-back aluminum seat (1, driver’s side) with fasteners
  5-point Simpson brand harnesses. 3” wide driver only, frame mounted with fasteners
  Emergency brake boot, black leather
  Authentic interior rear view mirror with fasteners
  7-piece electronic gauge assembly
  Authentic polished SS shifter handle, shift knob, boot, polished ring and fasteners
  14” competition steering wheel (listed in steering assembly), with polished aluminum boss and small center badge

Exterior Accessories and Lighting:

The MK4-R Competition kit is loaded with the right parts on the outside.

  Competition tow hooks, front & back
  Authentic chrome-on-brass vintage windscreen, tinted with side bars and fasteners; DOT safety glass compliant OR vintage driver’s side competition windscreen
  Authentic style three-lock set including T-trunk handle, L-shaped hood handles, matching keys, cam wedges, fasteners, latch pin sleeves and plastic end cap
  Authentic license plate light and bracket with fasteners
  High-quality laser-cut aluminum side louvers
  Circle logo badges for nose and tail
  Original style headlamp assemblies, including buckets, halogen headlamps, trim rings, and fasteners
  Original style front amber turn signals, and red rear tail-lights
  Lighting is DOT-approved
  Authentic bullet style sideview mirror

Complete Pedal Box and Components:

Leaving the Mustang pedal box behind, the complete MK4 kit utilizes the proven Wilwood brand pedal box with fasteners and all the required ancillary parts

  Wilwood pedal box with adjustable pedals and mounting hardware
  Master cylinders, clutch quadrant, clutch cable
  Accelerator pedal, accelerator cable, return spring and ball stud retainer, with fasteners
  Brake line adapters and T-fittings

Oil Filter Relocater/Alternate Drive Pulley Assemblies:

An oil filter relocation kit comes with all hoses and hardware.  Other parts to help 302 EFI and Mustang engine users include:

  Oil filter relocation mount with fittings, hoses, barbs and fasteners
  Spin-on engine block adapter
  Alternate drive pulley, spacer, pulley wheel and fasteners
  Air filter, conical
  Fan belt, six rib


More than 1,500 top quality zinc plated, chrome and stainless steel USS and SAE fasteners, numbered and packed individually by assembly.

MK4-R Challenge Kit Assembly Manual:

Bound 400 page assembly manual, also available in PDF by email.

What You Need

This list assumes you are building a car according to the configuration set forth in the NASA-FFR Challenge Series rules. If you are not planning on racing in the series, you are free to use a much wider assortment of options and running gear.

Major Parts

  Engine, Transmission, and Rear End
  Power steering pump
  Competition fuel cell for wheel-to-wheel racing
  Wheels and Tires


• Tow hooks
• Rear brakes
• Wheels (17×9 F/R to be Challenge Series legal)
• Wilwood brakes
• Mosier rear axle
• Full length headers
• Stainless side exhaust

Note: Not all options are Challenge Series legal. Consult NASA official rules.