What do you do when you have two months worth of inventory on your lot and brand new Corvettes and Cobalts arriving every day? You start to sell, sell, sell. GM is offering 0% financing for 72 months on outgoing 2004 models next week. Experts everywhere warn that such a sale could A: attract high credit risk buyers (Mitsubishi anyone?) and B: display the image of a discount appliance wholesaler. Neither is too rosy a prediction.