how well have you taken care of the car(i.e. 60k maintenance, oil changes, etc.) I think in general with 146,000 miles, if you have no mechanical problems, you shouldn't have lost much, maybe around 10hp-20hp(worst case scenario), we're talking about oil deposits and stuff like that I think. I think your friend and that dude you raced are full of sh*t. I could be wrong though...