I was thinking about getting a muffler from a 2001 maxima. Will that give me any extra horsepower and if so how much. It would be added with stone racing headers and y-pipe plus a cold air intake. Right now I only have the cia in.

 

Don't expect any significant gains by replacing anything from cat and back. 2k1 muffler will give you 1 hp if you get lucky, B-pipe might add 3 hp more.

 

i have a 2k1 muffler on my car for now, and it gives maybe like 1 extra horsepower over stock...