Let's put it this way, I sold my car earlier this year and I got $25000 for it. If you search the boards (svtperfromance.com in particular) you can find 03's all day for 25K. So if you do the math the 03 lost $10k in a little over a year. Another way to see what these things will be worth is figure out how old the car will be when (the year) you want to buy it and find a Cobra that is just as old Today and that is roughly what you will pay. This crap about collectors cars, etc doesn't mean anything to value. Heck, the Mystic Cobra I just bought is only worth $10k or so the book says. I paid way more than that because it was a great condition, low milage car, etc.
Bottom line is if you want an 03/ 04 Cobra value of the car will be on your side, I would say that in late 2005 you could get a 03 for the HIGH teens, low twentys
Just my opnion