Words by Cody Hooper, photos by Jon Crowley
Marshall Motoart’s Superleggera is unlike nearly every other custom Polaris RZR XP 1000. Builder Chris Burke replaced the factory steel chassis with a hand-built aluminum structure, converted the cab to a center-seat layout and added a K&T Performance turbo engine reportedly producing approximately 300 horsepower.
Marshall Motoart has been creating unconventional off-road vehicles for years. Founder Chris Burke has a talent for blending functional fabrication with rat-rod influences and a style all his own. One of the company’s best-known creations was a dramatically lifted four-seat RZR powered by an American V8.
For the Superleggera, Burke went in the opposite direction. Instead of making the machine larger and heavier, the goal was to remove weight, lower the profile and concentrate an enormous amount of power in a radically reshaped chassis.
Building a RZR Around an Aluminum Chassis
The project began with a new Polaris RZR XP 1000 and an assignment for the “Project X” segment on Destination Polaris. Burke had built several wild vehicles for the show, but he wanted this one to surpass everything Marshall Motoart had previously created.
Almost everything except the RZR’s plastics and drivetrain was discarded. A shipment of aluminum stock arrived at the shop, and Burke began turning a rough sketch into a complete one-off vehicle.
The idea was summed up by one word: “Superleggera,” Italian for “super light.” The name has long been associated with lightweight, high-performance automobiles, and it fit Burke’s plan for the RZR perfectly.
The centerpiece was a complete aluminum chassis that replaced the XP 1000’s factory steel frame. This was much more than a material substitution. Marshall Motoart substantially altered the vehicle’s dimensions and driving position.
The Superleggera became a single-seat machine with center steering. Its cab was narrowed approximately five inches at the front and pinched even farther at the rear. Burke lowered the roofline by 17 inches and stretched the chassis eight inches, resulting in a reported 105-inch wheelbase.
Those changes gave the RZR a low, narrow profile that looks more like an off-road missile than a production side-by-side. The long aluminum suspension arms extend from the compact central chassis, making the machine appear even wider and lower.
Approximately 300 Horsepower From K&T Performance
Building the chassis and suspension from aluminum created the opportunity for an exceptional power-to-weight ratio. To supply the horsepower, the RZR’s engine was sent to K&T Performance for an extensive transformation.
K&T installed an 1103cc big-bore kit along with forged pistons and connecting rods, performance cams, stronger head studs, CNC cylinder-head porting, larger valves and a large turbocharger. The completed combination was reported to produce approximately 300 horsepower.
STM Powersports Rage clutches transferred that power through the RZR drivetrain. A Dynojet Power Commander, AutoTune system and display handled engine management, while dual black Muzzys mufflers gave the machine an exhaust system that matched its extreme appearance.
With hypercar-like power relative to its weight, the Superleggera was built to do far more than sit on display.
Long-Travel Aluminum Suspension
Marshall Motoart fabricated an aluminum long-travel suspension that widened the RZR by approximately four inches per side. FOX Internal Bypass shocks measuring 2.5 inches at the front and 3.0 inches at the rear controlled the suspension.
Assault Industries supplied billet radius rods and tie rods, while Summers Brothers Racing produced extended 300M axles for the wider suspension. NXS Designs billet hubs and spherical bearings completed the one-off suspension package.
The original build did not include a verified suspension-travel measurement, but the long arms and large FOX shocks gave the Superleggera substantially more capability than a stock XP 1000.
Three wheel-and-tire packages allowed the vehicle to be configured for different terrain:
- 32-inch STI Roctane XD tires on 14-inch STI HD4 beadlock wheels
- 34-inch STI Outback Max tires on 17-inch STI HD6 wheels
- Fullerton Sand Sports STU No. 2 competition-cut paddles and matching front rib tires on 15-inch DWT Sector beadlocks
Single Seat and Center Steering
Inside, the Superleggera bears little resemblance to a production RZR. The factory two-seat arrangement was replaced by a single Triple X Venom seat positioned directly over the centerline of the vehicle.
The steering column was moved to the center, giving the driver a symmetrical view over the front suspension. The seat straddles the center tunnel covering the driveshaft, while an Assault Industries quick-release steering wheel, harness and billet controls complete the cockpit.
Marshall Motoart hand-formed the aluminum dashboard, center tunnel and interior panels. The fabrication is one of the most impressive parts of the build, with the exposed aluminum reinforcing the Superleggera’s lightweight theme.
Candy blue, white and black paint and powder coating give the vehicle a relatively restrained finish compared with its radical construction. Layton Autobody handled the wet paintwork, while The Powder Lab completed the powder coating.
First Test at Little Sahara
After K&T Performance completed the dyno tuning, the Superleggera was loaded onto a matching Aluma/Wasatch aluminum trailer and transported to Little Sahara for its first real test in the dunes.
The published build information listed a dry weight of 1,108 pounds in the original story, making the Superleggera approximately 270 pounds lighter than the stock RZR XP 1000 used as its starting point. A separate specification supplied with the build listed 1,180 pounds, so the exact finished weight should be treated as an approximate figure.
Either way, the combination of a lightweight aluminum chassis and approximately 300 horsepower created a staggering power-to-weight ratio. That figure included the large tires, Heretic and Dark Hour lighting, dual lithium batteries, Rugged Radios communication equipment and Rugged Rocks GPS.
Under full boost, the K&T engine transformed the Superleggera into one of the most explosive RZR builds we had driven. It charged up the dunes while staying on top of the sand and throwing a massive roost behind its paddle tires.
The car was unquestionably fast, but its impact went beyond acceleration. The narrow center-seat chassis, extensive aluminum fabrication and stretched long-travel suspension made it one of the most distinctive custom RZRs of its era.
Superleggera RZR Photo Gallery
From the Dunes to Hell’s Revenge
The Superleggera was not limited to sand. It later appeared at Rally on the Rocks in Moab, where its long wheelbase, wide suspension and center-seat configuration created an unmistakable presence on the sandstone obstacles of Hell’s Revenge.
Watch the Superleggera on Destination Polaris
Marshall Motoart Superleggera Specifications
- Base vehicle: Polaris RZR XP 1000
- Chassis: Marshall Motoart custom aluminum chassis
- Bodywork: Hand-formed aluminum panels
- Configuration: Single center seat with center steering
- Reported dry weight: 1,108 pounds in the original story; 1,180 pounds in the supplied build specifications
- Wheelbase: 105 inches
- Chassis dimensions: Stretched eight inches, roof lowered 17 inches and body narrowed five inches at the front and pinched 13 inches at the rear
- Engine: K&T Performance 1103cc big-bore RZR engine
- Engine components: Forged rods and pistons, performance cams, upgraded head studs, CNC-ported big-valve cylinder head and turbocharger
- Output: Approximately 300 horsepower as reported by the builder
- Engine management: Dynojet Power Commander, AutoTune and display
- Ignition: Energycoil ignition coils
- Clutching: STM Powersports Rage 8 Z1 clutches
- Exhaust: Muzzys Performance dual black exhaust
- Front suspension: Marshall Motoart plus-four-inch aluminum suspension
- Rear suspension: Marshall Motoart plus-four-inch aluminum suspension
- Front shocks: 2.5-inch FOX Internal Bypass
- Rear shocks: 3.0-inch FOX Internal Bypass
- Axles: Summers Brothers Racing plus-four-inch 300M axles
- Suspension hardware: Assault Industries radius rods and tie rods
- Hubs and bearings: NXS Designs billet hubs and spherical bearings
- Sand tires: Fullerton Sand Sports 13.00 No. 2 competition-cut paddles with custom-cut front rib tires
- Sand wheels: 15-inch DWT Sector beadlocks
- Trail tires: 32-inch STI Roctane XD and 34-inch STI Outback Max
- Trail wheels: 14-inch STI HD4 and 17-inch STI HD6 wheels
- Seat: Triple X Venom seat
- Controls: Assault Industries quick-release steering wheel and shift knob
- Safety equipment: Assault Industries harness and mirrors
- Communications: Rugged Radios intercom, car-to-car radio, Bluetooth audio, headset, helmet kit and GoPro cable
- Navigation: Rugged Rocks HD7 GPS
- Lighting: Heretic Studio halo headlights, Dark Hour Lighting LED bars and dual Smartwhips four-foot illuminated whips
- Electrical: Dual 16-cell Antigravity lithium batteries
- Paint: Layton Autobody
- Powder coating: The Powder Lab
- Trailer: Aluma/Wasatch 8114 aluminum trailer
