That ticket is very easy to fight.
Especially since the cop didn't have any sort of decibel monitoring device. Calibrated ear? It's a BS ticket plain and simple. It's not a crime to modify your car (check out the SEMA site!)
The only thing that might be against you is the time of day (I.E. like late at night) and the local ordinance for noise disturbance. Most cities don't have a solid ordinace on this though so there is usually no legal ground for them to stand on. They usually just expect the people to pay it.
If their is a place to plead. Plead not guilty and then ask the county to produce a copy of the ordinance, regulations, etc. Check you local laws...
