I put his header in as a stock replacement and I can give my impression. The build quality was actually quite bad...ugly welds and not that straight. If you gain any significant power then your factory cat(s) was clogged. It did come with all new quality gaskets. I did an accelerometer based test that did indicate improvement, but whether thats from replacing bad cats or actually from the header is unknown. Like other headers for the IS, there is just no awesome gains with this car.
I would buy it again, because frankly there arent any other good options to remain emissions compliant. I found it online for $435 shipped to my door. An o2 sim and megan header will cost nearly the same and probably leak.
Imo EVERYONE driving around on the street should run at least run one cat. I dont want to breathe stank ass emissions so you can have +3hp on a 3200lb sedan.
Last edited by JRTritsch; 04-22-2012 at 03:51 PM.