is it possible to install the downpipe incorrectly and still not have the CEL on? I had installed the HFC downpipe and tested it with P-Box. The numbers that i got was actually slower than a fellow 335i owner running stock. Like I had posted before I could feel the car pulling harder at high rev. is there any sign i should pay attention to?
Could it interfere with JB? At the time of the testing I had hooked my car up with JB but i had switched the JB off. Tks!