Hate to sound biased, by I think an MR2 is a good choice. If you get an AW11, the car is pretty easy to work on. The number of things you can do with the engine is almost limitless. Depending on what you mood you are in, you can go with a different 16v variant or a SC'ed one, you can swap in a 20v of some type (direct bolt in, and the harness adapter is only 200 bucks), or you can get a 3S-GTE, or a Toyota V6 of some kind.