i was looking into an apexi WS catback exhaust... and i have a 99 maxima, but apexi says that its made only for a 95-96... but i saw so many 97-99 maxima with it so i was wondering what kinda modifications do u have to make to make the exhaust fit?

my other question is how much am i expected to gain from a warpspeed y pipe.... and a apexi catback?

 

95-96 have rear o2 sensor threaded into the cat, 97-99 have the o2 sensor after the cat in a short 6"pipe that fits between the cat and the B pipe. You should be able to use the Apexi by having a threaded bung welded on the B pipefor the o2 sensor. I have a 98 and just got a Budget B pipe and it has a bung for the rear o2 sensor in the front section of the B pipe, eliminating the short section of factory pipe with the o2 sensor. All that said, why not just buy another B pipe setup made for 97-99's anything special about the Apexi muffler and pipes?