i ask this cuz i happen to have come across a free budget y pipe but it's for a 4th gen and i have a 2k2. will this work and is it worth it?

 

Im 99.9% sure it wont.. after all, there are different ones for each generation, if companies could use the same one for 95-2003s then they would.

 

no, not compatible it also depends on what kind of emmission controls,
different size engine too

 

Different sized engine has nothing to do with it. The Ford 4.6L and 5.4L are the same engine, but the 5.4L is stroked.

 

what's your point? same exhaust manifolds? 4th gens came with fed or CA spec emmissions 02's and beyond only came with CA emissions... so and both use different y pipes. They may route different. If it's the same then why do they make different ones for different model years, besides the fed/ca spec emission issue.