you need to go to the shop where you can paint your car and pay for all the wings for extra downforce. once you get all the wings(front, back and sides of car) you can go to tuning and increase the downforce on the rear to 20(roughly, find out what suits you best). i cant change the downforce on the front for some reason but i have paid for everything available. also pay 20,000 Cr. for the anti roll bar which helps stiffen up the front end, you have to go to suspension to customize the anti roll bar setting. if you do this and all power upgrades you will have a beast of a motor, 882 bhp, not 100% sure on the best suspension settings but i know there a few people on here that have posted thier best setups