i thought theyd use bulge seats too but american muscle sold me regular chrome acorns for the bullits i bought from them. after turning down the end of the rotor, i didnt need any spacer, its tight but nothing rubs. i cant get a center cap to fit though. my inside weights did get a guage from the grease fitting on a good pothole the other day but they didnt get ripped off nor did the grease fitting so all is well.