Well, with 27K miles, you should be doing it for the second time in about 3K miles. It's pretty unlikely that you can hear a valve tick from being slightly out of adjustment, unless you have a much more serious problem. Given that your header is so close to your fire wall, well the part that you ussualy smack on the ground any way, you may be hearing some hot air escaping, often when hot and cool air colide, they make a strange popping noise, or hissing depending on how big a hole, and how hot the exhaust gas. Could be a lot of stuff, but you may want to take it in to acura and have them take a look if you can't figure it out on your own. Good Luck.....
Aj