I have seen a lot of conflicting information posted on message boards and websites about this fine automobile. I've decided to do what I can to demystify it and try and lay down some hard facts with supporting evidence about this car.
How many were made, and how many are still "alive"?
I've seen many claims that there were 3 cars made, and 2 of them were destroyed during testing. There seems to be a be some pretty good evidence that this isn't the case. Although I believe the 3 cars claim is quite possibly true, I don't think it's true that there is only one left, why? Well there are pictures around of two clearly different cars, both in museums, and by the quality of the pictures I'd suggest they're not from the mid 80s, but more likely from some time during the 90s or possibly the 00's. Also the picture of the white one quite clearly has a mid 90s Corolla WRC car in it.
The third car, which it appears quite possibly was destroyed as I have not seen any modern pictures of it, is this one:
Although you could try to argue that this may be the same as the black one pictured above, more pictures of both show a number of differences, such as engine layout, layout of parts in the engine bay, different exhaust, and some minor bodywork differences.
What was the engine and drivetrain layout?
I have read claims that of the 3 produced, one had a longitudinal engine and was 4wd, one had a transverse engine and was 4wd, and the other had a longitudinal engine and was RWD.
I believe that the white one was longitudinal engined and 4wd. You can see in this picture the CV joint coming out of the front diff:
In this picture you can see the heat-sink type fins on the front of the front diff:
In this picture you can clealy see the longitudinal gearbox. There are no good shots of the engine but from pictures of the exhaust manifold you can see it is longitudinal
This black one is obviously also longitudinal engined, as you can see in the following picture
After some thought I've decided this is probably 4wd too. I believe the visible part at the back of the gearbox is the transfer case that sends drive to the front wheels, it is similar in shape to what you see on a W56F 4wd gearbox, but without the rearward output for the rear wheels (I'd imagine the drive for the rear wheels would exit from an integral diff placed possibly just below the input shaft, similar to the front diff on a Subaru gearbox.
The other black one is obviously transverse engined:
The engine also looks a lot tidier and more modern. It is interesting to note how centrally the engine is located, and that the gearbox would seem to be on the RHS of the car, unlike almost every transverse engined production model Toyota. There are no clear enough pictures to decide whether this is 4wd or rwd either. However if you look closely at this picture you can see what looks like the gearbox extending to the left well beyond where the flywheel would sit (judging by the engine picture above). This suggests to me the presence of a transfer case, which would make it a 4wd.
So what engine is used? 4T-GT? 503e? Something else?
This is definitely a tricky one for me. I've heard a few people say it was the 503e but personally I think it was probably a 4T-GT. The problem is that the 4T-GT is 2090cc, and most sources say these engines were only 2L. It could just be a matter of incorrect rounding, or maybe they sleeved or destroked the motors. The 503e doesn't seem to be of the right era, whereas the 4T-GT seems to have been the race engine of choice during the 80s. The engine also looks nothing like any pictures of 503e's that I have ever seen. Some (all?) 4T-GTs had twin spark plugs, which it looks may be the case in the picture above. I have recently found a book about race engines from the 80s that has information on the 3S-GT race engine, and it seems possible it could be this too. I'll add more info on that later.
That's about all the useful information I can come up with right now. I have started a public photobucket account that I have filled with all the pics I have of the mr2, feel free to have a browse