Precats on a 2002

From what I have gathered from other posts my precats are in the exhaust manifold, whereas 2001 and below they are in the y-pipe?

Is this correct and if I gutted the manifold could I see similar gains compared with a 2000 maxima adding an aftermarket y-pipe?

Thanks

i'm not sure where the precats are on a 2k-2k1 but a 95-99 is on the y pipe and the 3.5's are on the headers.
as for gutting the header, you'd see some gains i suppose but the aftermarket y pipes are a little lighter and are mandrel bent for a better flow. the 2k2-2k3 maxima's are seeing 8-12 whp from the aftermarket y pipe regardless of the fact that the precats are on the headers.

Older Gens where the precats are in the y-pipes are seeing a 15whp increase. I am thinking gutting the headers and adding a y-pipe should compare to, if not exceed, those gains. I am just concerned if I gut the manifold there will be an noticable increase in cabin sound. Although I guess as long as I leave the exhaust somewhat stock it should be negligable. I own a cougar currently and I gutted my precats and saw a little increase in power. I am thinking of not only gutting the manifold but porting the exhaust opening of the manifold that bolts tto the heads. I am new to these cars and if somebody can please chime in who has experience with Maximas it would be a big help. With these mods (manifold gutted and ported, y-pipe) I think I could see some good gains (even on a stock exhaust).

People please chime in :)