Secondary cat delete, 409 SS tubing?
Hi there guys
Stock 335i apart from JB4 BMS DCI.
Im getting on the golf tee mod but I'm also going to a sec cat delete for a bit of a louder throatier sound, gonna weld them back on when i get catless DP's.
I have a e92.
What is the diameter of the piping needed?
and I've heard the factory use 409 SS tubing? If not what would be okay to use? thanks