I thought about taking my Volkswagen Sharan with me when I moved last august to the US. Point was that we had an extra car in Germany, I needed one in the US and we figured that selling it wont bring much (either that or the other car) but it is an amazing nice, great gas milage, comfortable, pampered car.
Anyway, it would have cost me about 5k including shipping, plus even I capitulated first with the paperwork (and I am usually pretty good at it). Plus, you do need about a week in your port of entry if you do it yourself, or you pay another ~1k to the shipping company.
If US soldiers go back with their old cars, Uncle Sam pays all of this. Friends of mine moved last year from Germany to Florida, and they took 3 cars back with them. They even do not have to follow the whole emission thing!!
Should you decide to do it anyway without the pick-up program offered, only do it thru a good import company, or you wont be happy.