no check engine light for me, sounds good no rasp small pops, worth the money

mfs still threw a check engine light after 5 days

No CEL for me on a stage 1 tune so far. They do produce a slight zingy sound at WOT, but that may go away after they are “ broken in”. They bolted up perfectly with my aftermarket dual exhaust on my G37S convertible. I also passed emissions test with these. I don’t notice much power gain tho. The sound is a little deeper.