the car at the top of the thread is the Marcos LM600, from england. it was designed for FIA GT racing and uses a 6.0 litre chevy motor. the car is a 6 year old (or so) design and has done moderately well in europe, where it is still used in the FIA GT series. Marcos did build a street version of this car as well to make it legal, but the company went into bankrupcy last year (2001), although there was talk of a dutch consortium buying the company and moving production to the netherlands. the company's website still works, a google search chould turn it up, it's worth a look at.
the 4 cylinder in the supra isn't exactly the engine used in the MR2. it is closely related, yes, but is closer in relation to the WRC motor from the Corolla and the GTP prototype motor from the early 90's, actual power is something over 600hp. at least this is based on everything i've been able to learn about the JGTC supra...