personally i like dual tip mufflers, i don't like big single tips and if you get the right kind, the dual tips almost look like they could have come stock. the problem is that for civics you can't get a full cat-back system with dual tips unless you get one of the cheap brands. the best way to do it is to just get a good universal muffler and get the piping done by a shop.
here's a pic of mine just for a reference.
my muffler is an OBX-R, it's got a 2.5" inlet. don't know the exact size of the outlets on the tips though. soundwise, it can be pretty hard to carry on a conversation at highway speeds (especially with back seat passengers), but it's still not as loud as many exhausts that i've seen.
props to a fellow horizon grey by the way! :number1