So I talked to my dealer yesterday. I've decided (after much reading up and such) to go with the Stillen exhaust, and when I told them what I was planning to do they said it would void my warantee. Now, I quite confident that the G35 is a well-built car, so I don't have to worried too much about a warantee. However, my big question is will the new exhaust (Stillen) make a big difference like the installation of the AEM has?

sounds like you're dealer is being a hardass. is the minimal power gains of a cat-back exhaust really worth the potential future hassles?

i know all about magnussen-moss, but the dealership can still make life hell for you if some sort of problem does pop up in the future.

Exhaust wont void your warranty... Those idiots at the dealerships are so irritating.

A big difference how? HP wise? You will not see a big difference in HP at the wheels with just an exhaust.

BTW, your dealer is full of sh*t.

Thanks for the input.
Like I said, its no too big of a deal. Besides, I did not get the info from the head of the service department, but the guy I know at the service department. He said engine mods, exhaust, or tranny mods will void the whole warantee. But come to think of it, I had my AEM installed when I brought it in to the dealer to get a side skirt fixed (which was fixed under warrantee!). hmmm...