Thanks for the info. I was considering 2.75, but if Magnaflow uses 2.5 even on the M3, it should be enough for the M52 to breathe. __________________ "Never trust a big butt and a smile" 97- 328Ti (daily) 01- S2K (auto-x, cruiser) 96- JDM Integra SiR-G turbo (1/4 mile, auto-x, road course, show) |