The new header arrived and I noticed that about a 1/4 inch of each tube is covered by the opening of the header flange. Does anyone know if it would be ok to grind out the flance enough to increase the exhaust flow?
Thanks we are new Mini owners and are having fun buying mods for it.

 

No need... as long as the opening of the header flange matches the ports of the head. Your primary pipes are most likely of large diameter. 1.5 inches seems to be the best diameter for flow and gas velocity for stock head. Stock is 1.25 inches.