Advice on exhaust?

FricFrac

I just picked up my 370Z a few days ago and I absolutely love the car. The one thing though that is driving me nuts is the exhaust. I loved the sound of my straight six in my '81 280ZX. I just had a header and a custom 2.25" stainless exaust no cat and a high flow muffler and a Monza tip. I'd like something similar for my 370Z - something growly not totally muffled like the stock exaust. From the sound clips I've heard I don't recall any down shifts and that's one of the sounds I really like - the pop pop pop of an unrestricted exhaust.

So I guess my question is first off is the stock exhaust going to unmellow? Secondly do I need to do a Cat back or is there a set of replacement mufflers? Can I do a staight pipe from the header to the muffler or is there some (other than polution control, etc) reason why the cat needs to be in there? Is that what they are refering to as a test pipe? Thirdly what would be a fairly agressive sounding exhaust? I'm concerned about HP but I also know that unless its being tracked by a good driver 5 or 10 HP isn't going to make a lick of difference in real life so I don't care if one exhaust peforms 3 HP better than another.