You can take an additional coverage plan out and pay extra yea on some added items ( rims, stereo system ). But the Insurance company does "Want" to know ( key word there). So they can raise or even drop your policy. If you even add after-market wheels, they want to know. If it comes out that you have done anything to your car, they want pictures of the car or they will send out a field Rep. to inspect it. So mod at your own risk.
