I'm starting to make the first steps with this project, the donee isn't an MR2, but my 6th generation Celica:

You may notice a 3VZ-FE sitting in there. This is something I started and finished a couple years back now, it's been perfect and runs nicely. No real reason to get rid of it, but I'm getting restless without a project, so it'll have to make way for progress.
Incidentally, if you want to buy a full Celica V6 swap package, let me know.

Onto the Audi,

There's a bit of a story about getting this home. I bought it on eBay in with a broken gearbox, no tax and 'locked out' but with key. £895 + £270 for a 400 mile round trip recovery. It turned up at about 11pm and dumped in the road. After trying various 'safe' methods of gaining access it appeared a window will have to be smashed. Half brick and feet just bounched straight off, the side windows are all laminated glass, like the front screen. In the end I got my 2m steel engine support bar and battered through the glass. Door open, key in ignition, doesn't turn, looks like this key only opens the boot (didn't unlock to door either). So the wheels are locked, and I need to move this thing onto the drive, more faffing, getting late, already dark. I grab the trusty angle grinder and chop through the steering shaft. Thankfully I had a bunch of friends rallied for the occassion, and used the procedue, 1) Jack up the car, 2) Steer the wheels, 3) drop the car, 4) push the car, 5) Repeat, we eventually got it onto the drive.
I've since started pulling bits off that are not needed. I want to hear the engine running and try and simplify the wiring while in the Audi as I'm currently (and perhaps naively) hoping to keep the Audi ECU. While pulling everything around the ignition barrel apart I got to this:

The fat white cable leaving to the right had be wondering, but now I'm sure it's one of those 'make sure you start the engine while in park' jobbies, and maybe I could have unlocked the steering lock with the key anyway, but as you may remember, this car was bought with a broken gearbox, and I can't move the selector into park anyway, so I'll need to pull the selector apart to find the other end of the cable to operate it manually.
Moving onto the theoretical bits. I've been having a little think about the transmission side of things, 4WD is a must, because it's a Celica, and just should be 4WD by rights. The Celica wheelbase is 2535mm and width is 1750mm, looking at the Audi A4 quattro, bellhouse patter matches the V8, wheelbase is +80mm longer and -20mm narrower, which should, without too much tweaking, but the driveshaft ends near each wheel. Then I'd need to make an Audi/Toyota hybrid hub to join it all together, but as I said, this bit is theory at the moment and may need revising.