Quick tuneups, go with the horsepower upgrades and the racing transmission. Add all the horsepower you can from N/A tuneups, exhaust, and other engine mods. Then buy the racing tranny, and tune the gears accordingly. There is plenty of advice about tranny tuning, do a search. That is a quick and dirty way to go faster. I don't much about the drag, car height, downforce, and other suspension issues involved..... But there are plenty of people here to help with that. Good luck!