are there any similarities between the 5th gen monte carlo exhaust routing and grand prix and newer monte exhaust routing?

 

I don't believe they are the same. Your Monte is considered a 1.5 Generation W-Body and we are a 2 Gen

 

darn. you gotta admit they look afully similar from the bottom

 

Back in the day I tried to install a 2nd gen W-body d/p and it wasn't even close to fitting properly sadly. The d/p has a different bolt pattern that doesn't fit our 5th gen exhaust, and the d/p doesn't clear the underbody either. You could use a plasma cutter and cut the underbody to make the d/p fit, just like we have to do to get headers to fit on L36 Z34's. Other then the d/p, I'm not sure how the rest of the exhaust system would work.