I agree about the S model. Just so much more car for the money. A car is what is worth is what you want to pay for it. You always haggle over the price...this comes from the old horse n' buggy days. No one ever pays asking price, so you need to know your car of choice, the year, any problems that it may have had. Go to Kelly Blue Book and look it the Private Seller Price, the Trade-In Price. Now wholesale can be 10-15% below the trade-in price and you need to be a dealer to buy at auction. So, I would pivot off the trade price and go 10% under and then see were it leads you to.
