Need Advice on Exhaust...

[extreme4life]

First off I was wondering if the Maxima's exhaust system could be swapped with the I30's?

But the most IMPORTANT question I have is what exhaust parts (from the headers to the muffler) should be upgraded first? I need to know this because Im on an extremely low budget so theres not much I can do, so I was thinking about just upgrading the headers and the Y-pipe but Im not sure if this will work or how much good it would actually do?

[sprocket]

What year?

[ddiamondd]

ive got a 98 maxima se. exhaust is something ive been looking at too but am not sure which part to do first.