When before I installed my Magnaflow I looked into one end and saw right through it. I first thought that I made a mistake and this will be very loud. I was wrong. It is just right and I am really getting better gas mileage plus performance out of it. Just my experience.

 

Ditto to the Gibson. Look at the swept side exhaust from gibson....www.gibsonexhaust.com has lots of helpful info on their site about noise levels, even sound clips....they advertise being the quietest performance exhaust...but still have that nice burble. plus advertised performance gains of 16 hp and 15lbs of torque. very nice sound....they also have some a bit louder, which you wouldn't want. hope this helps. Ciao
Nimrod