[GotRice?]

yes... if u go on the sentra forum all 02-06 se-r and spec v owners will tell u to get a aftermarket header with no cat or get aftermarket no cat header and get a muffler shop to weld a cat further down the system to prevent the problem... and there is the famous butterfly screw problem on those QR25DE engine... the butterfly screw will unscrew itself, i guess from vibration and goes into the cylinder and scratch the sh!t out of it...