You failed to mention whether you have the V6 or V8. I have an '06 LE (V6/AWD) and covered what I did to my exhaust in this thread, which I really need to go back and update, but the exhaust is fully covered:
http://www.thenissanpath.com/viewtopic. ... sc&start=0
I went with Doug Thorley shortie headers and mid-pipes, keeping the stock upstream converters. I cut out the main muffler and installed a Magnaflow #12580 (two inlet/one outlet) and had my friend fab the pipes going into it. I kept the factory post muffler. At first it doesn't sound the best, but at around 1000 miles, the muffler "breaks in" and sounds much better. At idle, it has a subtle rumble. At WOT, she sounds great! But, keep in mind, no matter what path you choose to free up the exhaust, exhaust "drone" is almost inevitable. For a while, you get used to it, but, it can get a little annoying afterwards, at least so, in my case.
Gibson makes a cat-back exhaust system, but it's a little more money.
One thing I've been looking at is the possibility of the V8 cat-back factory exhaust working on the V6. It's a shame I don't have a V8 Pathy to which I can compare. I know the mid-pipes (or, rear converters) are shorter on the V8, but that may not be an issue as the exhaust on the engine is different as well. The muffler should be in the same place, which is a 2-inlet/1-outlet design and the rear pipes should be the same, as the body is the same. They both use the same style, flange connections at the front and it looks like they "may" be in the same location, based on diagrams I've looked at. The mounts also appear to be in the same locations. If it would work, this would provide the elimination of the "restrictive Y" we all want to eliminate but still keep the sound level more moderate. Of course, the factory V8 muffler and pipes is not cheap; I priced them online at around $875 without shipping and not including gaskets. If somebody replaced their V8 system with an aftermarket and was selling a good used system, it might make it more feesable.