I have been reading alot about the magnaflow catback system, I'm wondering if anyone has just changed the stock muffler and noticed any hp gains. 2nd question is those that went with the magnaflow catback, did you have to get rid of the factory resenator and did you have to alter the exhaust pipe to fit correctly. I have read where some had to start heating and bending to avoid rattles, etc. My experience has been when you have to start modifying you can get into trouble. Just looking at options, if just a muffler will do the trick with the stock 2 1/2 inch exhaust then I may go that route. I forgot to mention I do have the GM performance upgrade.Thanks for any input.

 

The stock SS muffler flows quite well and, mercifully, doesn't sound like the fart can typical of small motors. You really have to go to a DP and high flow cat to extract a meaningful amount of power from an LNF.

 

3" catback with already having a 3" catless downpipe usually only gains 5-6whp, less with catted dp, even less with stock downpipe. that's with it being tuned in, if your looking for power get a cetless or catted downpipe and swap to stock for warranty work.