Whatever you do, as you are in CA, remember that anything over 95 dB (measured 18 inches from the tailpipe at a 45 degree angle) violates the motor vehicle code. There was a thread on this a week or two ago. I think it is a $1,000 fine that can be reduced to $200 if you pass a secondary state test. Still, how often will you see CHP conducting such a test with properly placed and certified equipment. They might have such a program but there are around 30 million registered cars in CA so your odds of not being caught are pretty good. And, if you are around the limit, and care about being nabbed, with the ability to turn down (via PSE) the muffler sound you are even safer. Best of luck!