NIsmo exhaust is gonna cost you in terms of money though, the cheapest I have found it is here:
http://www.leeparts.com/nissan_altim...st_system.html
and here
http://www.nissanautosports.com/niss...m-897-prd1.htm
Dealership is gonna charge you around $900+ and then another $200 or so for Installation.
Best option, at least the one that I am gonna do later on is buy it online and then take it to the dealership and have them install it, Ill save money with that option...plus its the only option cuz shops around here wont install customer bought parts due to liability/insurance issue.