I've spent more replacing the transmission on a $30,000 VW than at 5 year old subaru would cost.
Will never won a modern VW again. If the engine is in the rear its ok.
On the other hand my subarus kicked @$$, cheaper parts than VW/MB.
Has he considered the Grand Cherokee Diesel? Same engine as the mercedes, super quiet, clean, great torque, great mileage. Leftover 08's with 4wd have been selling in the 25-30k range with all the options.......some thing to consider.