Race Car Replicas recommends a GM LS V8 or a twin-turbocharged Lexus V8 for its Superlight Coupe kit car
The "engine bay will accept any longitudinal engine trans package", but RCR themselves recommend something from GM's line of LS engines, such as the mighty 7.0L LS7 from the Corvette Z06. Alternatively, the engine bay will also take a twin-turbocharged Lexus V8 engine, which is RCR's second choice for what to put under the hood.
With air-conditioning, G-force sensors and a 6-point rollcage, the RCR comes with most features you would expect in an upmarket sports car, however, purchasers will have the option of putting in their own gearboxes, and specifying the interior layout and feel. A popular choice is the Porsche G50 gearbox, however the engine bay is also large enough to hold the larger and stronger Ricardo gearbox from the Ford GT.
RCR will also be providing as an option a fully trimmed production supercar-type interior, with a choice of colors and materials available, including leather and suede. In terms of actually registering the car in accordance with compliance requirements, the Superlite Coupe comes with approved glass and lighting, a front splitter with an approved radius for safety, a compliant digital instrument cluster, compliant latches and other features that should make registering the car simple.