Well the way i look at it is.........They are all just a bunch of money making greedy b.a.s..ta..rd...s!!!! I can understand if it is a serious engine modification such as "turbo" or "supercharger" that u should inform them about it, due to the fact that it may be ridiculously over powered for street use and or it may have not been installed or engineered by a qualified mechanic!!! But when all you are doin is just changing the asthetic qualities of ur car to suite your tastes then why not???? It all just comes down to the fact that in their eyes it raises the value of ur vehicle and may make it more at risk of theft....But if sumone wants to steal your car it doesnt matter wat u own!!!!Also i had a case b4 i bought my rolla where i thought i would test the waters and see just what i can and cant do and or wat i can get away with; i asked about how much would my insurance cost me if i had an aftermarket stereo put in my car and they wanted to raise my insurance up by around $200?????WAT THE!!!!! Your just replacing a standard part on ur car to sumthing u actually like its ur car why cant you!!???