A compromise courtesy car for a few days is fine, but when it stretches into the weeks for a repair, you want something of a decent size. Most dealerships can find you a Passat, and they rarely come with less than 140PS TDI engine.
You will usually find that most insurer approved repairers are decent - the insurance company doesn't want you going back for remedial work, and don't want to pay out on the 5 year warranty some attach to the work. I'd get it in writing that they will not use anything less than new VAG parts when a part needs replacing as part of the repair.
