Well, I took it flat out on the freeway for a few miles yesterday. Hit 63.5 mph according to GPS. I think it had another one or two MPH to go, but I had to lift my foot a couple of times for traffic.
I exited the freeway, pulled over, and touched the engine lid-- HOT! No funky smells though, and no smoke-- engine isn't the cleanest either.
In my past VW's, and my current 912, the engine compartment is pretty well sealed off from the exhaust pipe. Mainly because the cooling air is sucked into the fan from the engine compartment.
I would definitely be interested in your mechanics opinion.