The first gen MR2 (AW11) is fairly accurate. However, the in-game grip provided with comfort soft tires is a little low compared to the one I have parked in the driveway. My personal MR2 has
a set of these bolted on right now, and they're equivalent to sport hard compound in the game. The gear ratios are 100% accurate, but the weight and power are for the JDM model. Limiting the power works just fine for conforming the stats to your market. Because it's such a small adjustment, it hardly messes with the power curve. Add the proper weight, and leave it centered. The reason the Japanese model was lighter because of body weight, so the heavier model still has the same distribution.
Naturally it isn't quite as fun to drive in GT5. The first gen is praised as the best MR2 in terms of driving feel because of its direct steering (no power assist) and lack of driving aids, so if you have an AW11 in real life it might be a bit of a let down.