do the intermediate pipes on my car need to be changed if i get new headers, y pipe , high flow cat and cat back? is the only intermediate pipe between the y pipe and cat?

 

The intermediate pipe is between the cat and muffler.

The RS I-pipe is too small for anything over stock performance. Get all of your aftermarket exhaust parts for the '86-'90 TPI single-cat application and you'll get the "good stuff".