A muffler shop could probably do it but it would probably be a lot easier to just get an exhaust for your hatch. The downpipe, cat and B-pipe isn't hard for a muffler shop, it will be the length of the final piece. The Integra (and Civic coupe/sedans) have a longer ass end than the hatchs. I put the tail piece of my Tanabe RM on my coupe one time because I needed a muffler and it was about 6" shorter. I just tied it up with wire so I could drive the thing and it worked fine. If you tried to put the Integra exhaust on, it would probably stick out past your bumper by that much (never tried so don't quote me though).

Here's what you need for the front part. I had the little extension on the right made for about $40 from a muffler shop on my hatch. Seeya.