Hi, welcome to the MR2 world, dont let a turbo owner ever let you think that the NA is any less of a car, they are crazy fun. Now, normally people would stab you and direct you to the search button for most of your questions, but ill try my best...
1. This you're gonna hafta research yourself, all I can do is recommend a Gen III J-Spec rear clip.
2. I'm a big fan of KO Racing, Greddy and good ol OEM products.
3. When it comes to shocks you need to be more specific on what you want and how you're going to use your car, again, research.
4.
3S-GTE Power Primer (READ IT) But most people would tell you to start with a MBC and disable the fuel cut, then maybe a downpipe and exhaust, an intake if you consider that a real mod. Then maybe a good turbo, like a CT20B or a TD06. After that if you still feel like you need more power... well, its in the Primer.
5. Lemme guess, blue interior? Best chance is a junkyard and get a whole new interior from a recently killed MR2. There are alot of those, alot of people jump into the MR2 fresh from the Honda world not knowing how to drive the car and that RWD and FF are night and day.
6. Scheduled maintenance, replace your Spark Plugs & Wires, and Distributor cap & rotor. All OEM, except for the plugs, go with Copper NGK's