sumaccord is right, i have Racing Hart C5s and man, my stock rims are heavy as CRAP!!!... dont worry man, i have a 1998 Accord 2dr(6th generation of yah don kno) I4... and i didnt lose any, and on turns i gained plenty.. =P i can turn like a mofo now. so get nicer quality wheels and u wont lose much or any, cuz u kno 18s even light wheels are still gonna be almost the same as ur I4 stock 15 inch rims, unless u got hubcaps, why is why many civics and integras go with those JDM tiny 15inch superlight wheels for racing, thus, if u get some cheap crappy one's... maybe alot heavier than stock, and u'll lose some-alot of acceleration