Firstly welcome, and rumour has it, that Zed is the fountain to youth.
One of my friends has a Nismo exhaust on his 03. I love the sound of it, a really nice throaty growl, sounds like it means business, but not in an obtrusive way. Can't liken to anything really, bit nicer than an Injen in my humble opinion. Also quite like the growl of the Borla.
(Yay, I found the old thread on our site in NZ, check this out, it has most of the big name exhausts with this reference site video clip
http://www.zmodified.com/gallery/index.php?cat=9)
Put is this way, I couldn't wait to take the RE040's off my 350, and I went with my favourite, Eagle F1-GS-D3's yet again. Aggressive directional, hugs the road really well, even in our yukky wet Kiwi winters and heavy Spring showers. Although it's like everything, personal choice and it depends on your driving style too.
Check out http://www.tirerack.com