I'd like to chime in on this.
I used to get tickets for this type of bullshit all the time here in SoCal.
You can get a ticket for the exhaust being too loud..
It doesn't matter if it is CARB certified or not. It is up to the discretion of the officer that pulls you over..
There was one time that I got pulled and cited for exhaust from a motorbike CHP. I promptly went to the nearest sub-station and had it written off not more than 30 minutes after getting the ticket.
What a stupid waste of time, and $10 dollars, but that is our CHP.. gotta love em.
As far as lowering, the rule is this.. (trust me, 12 tickets can't be wrong)
They determine if your car is too low by one of 2 ways:
1) The lowest part of the car (usually rocker panel or mud flap) cannot be lower than the highest part of the bottom of the rim.
Sounds confusing but basically if you had 50 series tires, any part of the car cannot be below the rim closest to the pavement.
2) The other criteria is the headlights. The middle of the headlights cannot be lower than 24 inches from the pavement on a flat surface..
Some cops have make shift measuring tape like the kind they give you at home improvement places with markings right on it.
Again, a fine example of our tax dollars at work.
Most of the time, the cops won't screw with you but when they want to be a-holes, this is what they used on me over a dozen times.
Be safe, and always try to smile at the cops, they seem to be nicer when you do.
-jeff-