...I would not trade in that '04 Coupe. You'll get screwed on it. The residuals on these cars has been hurt by the incentives on the new cars. But I think if you can get Private Party on it, you would be in good shape. What I would do, is e-bay off the '04 Coupe. You may or may not break even on what you owe (depending on how you financed it), but you won't have to roll over a big chunk of change into the new car, which would negate any savings you could negotiate.

E-bay off the '04 Coupe, take your 19 grand and pay off the loan, and then start from the bottom working the deal on the SRT. I would recommend calling another dealer across town with the exact same car to sell, and get them bidding against one another. Every time you get a new offer, call the other guy and tell him he has just been undersold. Keep it going, and I would not be at all surprised if you get that SRT for somewhere in the low thirties.