99-04 on a 96-98

What is the difference in exhausts from these years. I see 99-04 stuff, cat backs and mid pipes all over on craigslist but never 96-98. what makes them different? I'm thinking about buying them and just trying to make them work, has anyone tired to make the newer stuff work on the older cars?

 

So they're bent the same just different hanger location if that's all that's a cheap fix.

 

Thanks for the info