I have the lsj downpipe and GMPP catback. Its been on for over a year and have had no rubbing issues or CELs.

 

i have had a full lsj exhaust, exhaust mani, dp, and catback, wielded good #'s on the dyno, got 7hp and 19 tq out of it...now i have a obx header, custom midpipe, and megan catback, i gained 3-5 thru out the whole powerband, my peak dropped 2 in the mid, but in the end i was once more 3-5 above the previous dyno, megan ftw, will post vid in a bit

http://www.fquick.com/videos/viewvideo.php?id=5507

 

What year is your car? There are at least a few of us on CSS.net that have the GMPP catback and the LSJ DP with rubbing issues. It seems like less people have a problem with CEL's.

 

I have an 06 LS. I might go look when I walk out side but I never had a problem with it.

 

I've got an 07 LS. I dunno man. I give up on why I had rubbing and CEL issues, and most everyone else didn't.

 

when i had the full lsj exhaust i never got a CEL