I purshased them for my q50, paired with injen intakes and invidia cat back, the exhaust note substantially more aggressive and I can feel a bit more difference in performance

06 350z, Kinetex HFC +Tomei y pipe + Tomei cat back Fun, fast loud.

Bought for my 2008 G35X. Nice aggressive tone paired with top speedcatback, no check engine light either. Nicely built to. Car pulls hard all the way to 7800 rpm doesn't feel like the power drops off like with the factory cats

No impressed with the cardboard gaskets. I purchased OEM ones anyway. Only 8 bolts provided? According to my garage they aren't the correct size. Had to purchase correct size bolts. Other than that I'm happy. No CEL light, sound slightly changed mostly during warm up.