The Jeep and the Tuareg are not your only choices here. I'm towing with a BMW X5 diesel, and it works great. The tow capacity isn't quite as high, at 6,000/600, but it has all the pull you need for those loads. I just got done dragging out 5,000 lb, 21 foot travel trailer from Virginia to Rocky Mountain NP and back, and it towed that trailer up I-70 and over the mountains west of Denver like it wasn't even there. There's also a very capable Mercedes SUV in diesel.
All of these are 3 liter, 6 cylinder engines of European design, and all put out about the same power. You would do well to consider them all. The Jeep is probably the least expensive of the lot, but not necessarily the best choice. The Jeep engine is an Italian aluminum head, iron block engine from VM Motori.