I just spent all day putting in my stainless works headers and y pipe.............headers are great............the y-pipe did not fit. I did some cutiing here and there but would not clear the trans crossmember correctly so it would not tie in to the cat back correcly. i am off to the shop tomorrow to do some custom work from the headers back and put in a true dual set up.

 

stainless works or dynatech IMO

 

Do the OBX headers fit the Sierra Denali's? They are stainless and even though they are not listed for my truck, they fit great. Still have the 2.5" collector like the DT's. 2.5" is probably enough for most apps though.