[silver]

well sound doesn't relate to hp. The 5zigen is ok, but there are better. In terms of restriction, I have seen tests that show an impedence of airflow in some of their systems, but that is not due to lack in quality. I always like the tanabe medallion, maybe just because of the name though. Remember that whatever you choose is not going to make a huge difference unless you plan on doing FI or major modifications to your motor and airflow. I recommend you look at the styles you'd like and focus on looks since that is where you will find your greatest gain.

why don't you just get a muffler if you are concerned with sound and save the 300 dollars extra and do something else with it, like buy a bodykit. You can get a kit and muffler for under 500.