I'm dealing with a leak that "looks" like it's from the back of the engine, but what's really going on is either I'm blowing oil out the dipstick tube (Did not replace the O ring on the dip stick holder....) or it's leaking at the turbo oil drain back, and seeping down the block, running back along the pan rail, and then catching the bellhousing junction and dripping down. It is a very minor leak, and I think it's from oil being blown out the dipstick hole. (I was running 12 quarts of oil on this new setup, and now at 10 quarts, it is still too full for high RPM running extended periods.)
The other places it could leak is from the rear galley plug, or one of the other small plugs in the main galley. That are a biotch to find if it's a slow leak.
My engine does not make it easy as the thermal dispersant is a shiny black, and just looks wet all the time anyway. (Leaking oil pretty much blends in untill dust is stuck to the oil.)
If you can possibly handle it, stick with the MK3. I was at the drags last night, there were many MK4's there and a few MK3's. Most of the MK3's are ratted out, and getting old, but a few, like mine, are in great shape. And I got ton's of people coming up asking about the car. (The 18" wheels with 14" brakes behind them attracts alot more attention than I thought it would. Otherwise my car is "stock" appearing.)
I did not build this car for the looks, or the "looks great" comments, but they are nice to get, that's for sure. When this car is done, and painted, it will be even better I'm sure. (And the interior is done, but right now it does not look bad, but is a 1988 car.)
I'm actually thinking of stripping down an 87 NA hardtop body, cleaning it out, welding up the struture, adding a few reinforcements, and after it's all painted, transferring over my engine/trans and the best parts from both cars to end up with a basicly new vehicle. (I don't car if it's a 88 or 87, and having a NA VIN would be easy to insure... LOL) The hardtop is what catches my attention. Lighter, and stronger, and with some mods, much stronger than any Targa car will ever be..
I say, keep the MK3, and enjoy the thing. If you want a MK4, buy one, but you might find they are just as problematic as our cars in the long run.
On the "new" Supra? LOL If one comes out, it will be a Lexus, and cost more than two old Turbo's combined. It will also be a NA V8 car, as I don't see Toyota building another turbo car any time soon. (Possibly some kind of direct fuel injection, or supercharging, but no turbo's.)