First off, thanks for serving our country.
By the time you get back you'll not have to spend all of that money on a Crossfire, the market is full of them and you'll be able to find exactly what you want as far as color, trans, etc. I bet you'll be able to get an 05' w/ lower mileage for about $17-20K, no problem, trust me. I'm getting rid of my car this Monday and the dealership (Bavarian BMW in Shelby Township Michigan) is giving me $16.8 for my car and its only got 16.5K!
As far as a daily driver goes, well it depends on a couple things. One is where you live. I never drove my car in the snow because I have another car, a reliable beater car, so you must think about that first. Even with snow tires its been stated here before in anything above a couple inches, forget it! The next thing is your height. I'm 5'6" so getting in and out of the car isn't that much of a problem although it did take some getting used to. So as long as you don't mind "sliding into the car", thats also not a problem. Another thing to think about is maintenance. The oil changes are pretty expensive, but when you consider how long you can go on one of them it even out, so don't let that bother you really. Tires for the car aren't as expensive as you might think, even though they're 18/19's, the prices are coming down. The fact that the car is essentially a M-B is great and should be a plus when thinking about the car. The Mustang is a great car as well and I actually ordered one before I got the Crossfire. I ended up with the Crossfire because Ford screwed many of us around when they first came out, so I took the Crossfire. Its been a great car in the almost 2 years I've owned it needing only one recall, very minor thing with fan relay and it had the fogs replaced under warranty due to new styled ones through the dealership, both free of course. If I were you I'd take both cars for a test drive because they both offer something completely different. The Mustang is a muscle car and handles like it and the Crossfire is a grand touring car that can carve up the back roads VERY well. In addition to that I can honestly say I've been on many trips in my Crossfire, Chicago twice, Tennessee twice and WV and the car is GREAT on gas. I get anywhere from 28-33 mpg on the freeway, something to think about.
Again, good luck with your car and thanks again for your service, its MUCH appreciated!