Okay so I'm looking into a new exhaust system for my Civic, just a single exhaust. And I was wondering what's the big difference in a catback Exhaust?

 

If you're wondering what a cat-back exhaust is, it's just a term meaning "everything from the CATalytic converter BACK to the end of the muffler."

If you're wondering what the difference between different cat-back exhaust kits is, ther isn't much to know.

1. Pipe sizing: there are three common sizes - 2.25", 2.5", and 3". This is the most important aspect for performance gains. You need to order the correct size to match your existing setup.

2. Mufflers: some are a straight-thru design, others aren't. Some are louder than others. Cheapo ebay style mufflers (such as N1) sound like **** on naturally aspirated cars and will get you laughed at.

3. Resonators: some cat-backs come with resonators, others don't. A resonator is basically just a muffler that's installed in-line, not at the end of the exhaust. They greatly reduce noise with minimal power loss.

That's basically it. There isn't lots of "R&D" going into exhaust systems, no matter what the douche-bag companies claim. It's simply a mixture of those three aspects. Everything is mandrel bent with minimal bends, so that's not even an important consideration anymore.

It basically comes down to how loud you want your car to be. And whether or not you're turbo'd makes a big difference in sound. N/A cars with turbo exhausts sound horrible.