i have a straight pipe and im swapping it back for the stock cat or a magnaflow
it gets ghey after a while, it's loud with no real purpose
straight pipes are really beneficial to built motors but more so for turbo motors
god its annoying and loud
i have magnaflow high flow cat right now and havent had any problems so far. My stock cat was fcuked and throwing cel number. I went to dealership and ask for oem cat for ULEV engine and it was around $1000 dollar. I took the magnaflow, and it didnt throw any cel number no more.
P.S. i live in cali as well