I think the Curvesrgood's story explains well why these cars are so great. Those that know and respect great handling cars and are familiar with the MKI MR2 know just how good it really is. Unfortunately, it is overlooked by many simply due to newer and bigger engines that are available in more modern cars. But if you want a reliable car that can safely be built up to more than respectable handing and very good power capabilities, the MKI MR2 is the car.
The N/A can achieve stock 4agze power capabilities with some not too outlandish work (oversize higher compression pistons, reasonable sized cams that won't destroy your bottom end, improved exhaust, improved air intake, and possibly a little valve and head work). Combine that with its lighter body weight and slightly better front to rear weight balance than the 4agze and you have yourself one great car.
But handling and brakes must be improved as well to keep up with the previous suggestions. a) An old MKI will definitely need new suspension bushings if you want the car to handle properly with other suspension improvements that are likely to be made. Fortunately TRD still makes their harder rubber compound bushings and I highly recommend them. There are poly bushings, but for me they are too stiff and transmit far too much vibration when all other suspension mods are done. b) new strut inserts and springs (Tokico and Koni are the most popular struts and Eibach and ST the most popular springs). c) a new/bigger front sway bar with poly bushings and clamps (ST is the main player here). d) new stock brake discs are fine (aftermarket cross drilled and/or slotted units are available, but all use other than stock materials, that despite their modifications all weigh more than the unaltered stock units, so what's up with that?!). e) improved brake pads (many to choose from, but I am very fond of Porterfield, who make a superb non-fading carbon-metallic ceramic backed pad that stops you on a dime). f) rebuild the brake calipers as they tend to gum up after only 100k or so. g) wider and lower profile tires (15" rims with a proper offset and some 195-50-15 tires for starters). h) proper front and rear alignment with slightly decreased toe-in and fully advanced front castor for better steering response.
Do all that and you will have yourself one great car. Just look at how the MKI has been penalized in the SCCA, having to run against cars that have considerably bigger engines, and you'll get an idea of its potential. Hell, they penalize it just because it has a mid engine design which results in significantly better handling by itself!
But as previously suggested, start with the suspension first and learn how to drive the car properly. If you have been driving a front engine car up to now it will take quite a bit of learning to really handle the MR2 well (only because it will be opposite many of the instincts you have developed with the front engine models, not because it is really that difficult). Even with an old engine and a properly prepared suspension you will be able take on most comers in any sort of winding road situation. I especially like to watch the wannabes fall well behind on long curving freeway onramps. The fastest can certainly catch me once the road straightens out, but anyone can buy a fast car and drive it in a straight line. It takes skill and know how to build a well handling car and drive it properly.
Once that is accomplished start on the engine performance improvements. Try the bolt on mods first since they will generally be the cheapest and easiest to add. If you want a reliable car, don't get too outlandish with radical cams and crazy headwork. When the MKI is in decent form and taken care of it is extremely reliable. Those who have claimed otherwise have started with old cars that others have mistreated previously. I have had MKI's since they first came out in '85 and absolutely love them. I do most of my own work on them and find that once something is done right, it stays done.
Good luck!
