just smogged it and then had it installed after. In 2017 i may try smogging it with it on since i have a borla exhaust maybe they wont question it? It seemed pretty relaxed as long as the zzp cat passes the sniffer. if not ill have to swap. I tried installing the dp myself but no dice. The manifold bolts were hard to reach and get a good torque on. But maybe that was cause they were stock bolts?