Your best bet would to get estimates from local body shops. It shouldn't cost you anything. Nobody can give an idea w/o knowing the work involved, condition of the car, what exactly you are having painted (changing color, repainting the same color...?) and nobody should give an estimate w/o seeing the car in person...there are alot of variables. I'd hate to see someone tell you it only cost them $1500 to have theirs done when yours could be triple that due to the work involved. I could tell you that mine only cost me the clearcoat, but my dad has a body shop...heck you could go to Macco & pay less than $500. You get what you pay for in some cases...
You need to be a little more descriptive w/ what you want to do & what condition your car is in...& yes, some paint is more expensixe than others (mainly metallics & reds)...t-red $300+ per gallon (not including the clearcoat)
