Mazda RX7, a 4-star rated car which was at PR 534, I upgraded it's acceleration with 4 clutch plates (bought in 12 14 16 and 18k bucks) and 2 kits, it cost me 15000 bucks to install it and that dropped the PR to 533. I think it's time to leave this game which has so many issues which can't be posted here due to word limit. Moreover, no one from the developer side has ever replied to any of the complaints posted so far. See you on the other side slick.