Ok this is very tempting.
I have a 330i, I'm getting the performance exhaust installed soon. Now if I remove the primary cats.
How much more louder will it be with the PE?
The O2 sim, is there a DIY for the install?
With PE primary cat delete BMS PBX Charcoal delete KandN dropin...how much HP gain do you think I'll gain? Just an estimate?