That is usually what I read about that constitutes a horror story. Turbo resonator on a T1N -- fixable. Black death if caught early, fixable. If the vehicle's computer starts acting up... welcome to the world of pain. There are multiple states of limp-home mode, and some of them will not clear up until the vehicle goes to a M-B dealer.
I'm hoping the Ford Transit isn't this way, where a thrown code can be cleared up by a ScanGauge or equivilent, and doesn't have to be brought in the shop.
It could be worse though. With modern BMWs, I was reading that (and please correct this if wrong) if you just disconnect the battery, the vehicle won't start until towed to a dealer to be reprogrammed.