I've tried listening to all of the '07-'08 sedan catbacks (stillen, borla, magnaflow, hks, etc), I think I prefer the 5zigen and impul so far (although audio clips can be misleading, it's the best I can do right now). I like the impul because it retains the factory tip shape

5zigen

http://www.youtube.com/watch?v=XmpTu...eature=related

impul

http://www.youtube.com/watch?v=zS2jx...eature=related

 

What can I tell you...if thats what you like..get it and enjoy

 

holy crap, the cheapest I've found the impul is $2178.

and I thought my c6z vette was under heavy "taxation". $2178 would practically buy an "installed" camswap on the ls7

I honestly don't know what sound I want. I know the things I don't want:

fart can sized tip
fart can resonance
low rpm drone
bend you over, no soap on a roap in sight type pricing

what I do want:

proportionate tip size, oval if possible
no low hanging muffler
no low rpm drone
throatiness over stock (that shouldn't be hard to do, this sedan is way too quiet)
under $1000


looks like price alone is going to throw any of these japan bred options out the window.

 

stillen

http://www.youtube.com/watch?v=nvWKY...eature=related

magnaflow

http://www.youtube.com/watch?v=_KYT-...eature=related

tanabe (available for sedan, but this is a g37)

http://www.youtube.com/watch?v=6Mcl5...eature=related