Ive been debating on how to get my exhaust done. Since everyone seems to say that intake/exhausts hardly do anything to the xterra for hp and mpg do you think its worth it to replace the small diamater ypipe and get new pipes from the cats back? or do you think the gain would be so so small that its not worth the xtra money?

It's probably worth looking into, I know the main restrictive issue in the exhaust are the cats. Personally I have only one set of cats due to a set of headers I had installed, and I really realize the increased torque and hp my engine is putting out these days. I was looking into replacing the Y-pipes as well because having stock diameter piping hooked up to 2.5" piping seems a bit absurd. You should look into it and get quoted on it, see how difficult it is to actually do. Anyway, hope I helped at least some. On a side note, what pipes/ muffler are you considering?