uh did you forget that I have a 98 240sx with a KA24DE? Your Altima is 2.4l FWD, right? Yeah it sounds good with an intake but i think a N/A KA doesn't sound too hot with a cat-back. If it's just a muffler then it sounds just horrific.
i got dual flowmaster 40s Y'd off of a high flow cat and everyone says it sounds like a v8, when i really got a v6.
Didn't know you had a 240 I'll get to hear some Alty's at the next meet and judge for myself. If I don't like how the straight pipe mufflers sound will get a super turbo and be done with it. She seems to be getting better gas mileage since the inlet for the muffler broke loose. All I'm looking for are way's to improve gas mileage and increase performance a little. A N/A KA won't see huge gains with bolt-ons but every little bit helps. I know it won't suddenly become a speed demon Altimas are slow but the car is fun to drive.