I want to keep a car at a specific level. Its got everything on it except for the transmission, engine upgrades, and weight reduction. I'm mainly concerned with ruining the quality of drive and the sound of the car, especially since its pretty rare, which is why I've only tacked on a few addibles. What would be better, an engine upgrade (1 or 2) or weight reduction (1 - max)? Something that would give it that extra edge, but preserve the quality of the car.