Hi Chris, are you talking about the LSD deferential that [B]Mot27cars[/B] post it or you have one like that I need one for my car and I hope 3.07 will be a right with M3 engine and 5 speed that is on my car you know much better than I know please give me your opinion.It bolts right in and it is LSD and you have a 3.64. So 3.07 / 3.64 = 84% so a 16% reduction in RPM for easier cruising but less acceleration from a stop.