In your first post, you mentioned the "deepness" of the sound, and if a low pitch is what you're looking for, then BIG pipes are where you get it. Anything that increases your exhaust system's internal volume will lower its pitch. You can sacrifice performance with a low-pitch if you can't move your exhaust quickly enough through it because the pipes are too big. Honda motors are fuel efficient because they're very restricted. Too big of an exhaust system may work against you if it's not done properly.

I have 3" pipes on my car because it flows over 680cfms. It's a 2.0L DOHC with enormous intake/exhaust ports on the head and racing cams. In addition to that, I've ported and polished everything on this engine extensively. I need 3" pipes. If you haven't spent $5000 on forced induction modifications already, don't go bigger than 2.5".