I'm going to be installing Jet-Hot LT's, Coated Y Pipe, and a cat-back (probably GMMG) next month. The guy from GMMG recommended getting high-flow cats due to the smell and possible rasp that would be associated with !CATS. He said I may lose 4 horsepower or so, but it would be worth it because I wouldn't have to deal with the smell when the top is down.

What are your experiences / opinions??

 

You should change the post subject and put "question about gmmg exhaust" or something like that. You probably would get more replies jmho

I just installed lt header and orp and the rasp was terrible. I added a carsound hi flow cat today and the rasp is gone. Its a little quieter but well worth it.

good luck

 

You are asking for some trouble trying to put LTs on your vert. I gave up on the idea and am going to go with AS&M headers. Besides the factory SFC you have to deal with the massive tunnel brace that the verts have. You can remove it if you want to, but my vert creeks enough as is. You should go with som mid lengths and no cat, safe yourself from the headaches. Any car without cats is a little raspy, but on our lt1s, its usually a good raspy.

 

I thought minesounded fine without cats, I put some on eventually mainly because I feel better knowing I am helping the environment, plus the cats do smell better than raw fuel. The smell isn't bad without them, you can only smell exhaust at stoplights, and even then barely. THe car sounded great without cats-not raspy, I think it depends on what mufflers you go with, the more freeflowing the more raspy, also different designs wil change the sound. The tunnel brace is worthless, when I removed mine I didn't notice any difference, a rollbar or SFCs is a much better bet. Also the longtubes are great, haven't had any problems, except for the coating coming off