87 300E for sale in my area in which the owner put it the wrong battery and hooked it up backwards and he says he saw smoke coming from the alternator and it is fried. Car has now been sitting for two months. He just wants to sell the car since he is not mechanically inclined (needs rear windows fixed and the sunroof. Body is good, interior good, 150K miles. It has new tires, he wants $400 OBO.............He did hook jumper cables to it and it started and ran fine with all the lights working etc except the radio doesn't work now........Am I asking for trouble since the battery was hoooked up backwards. I know I will have to get a new alternator and rewire it but did this car just turn into a donor???