I know a guy who knows a guy that flat-towed a Mini Cooper S behind a motorhome. Unfortunately, one time he forgot to take the manual transmission out of reverse and didn't realize it until he was about a half mile down the road. Apparently, due to the reverse gear ratio, it spun the engine the wrong direction at about 12,000 rpms. It ruined the supercharger because, when the internals of the engine exploded, it tried to puke all the metal shrapnel bits through the air cleaner. The guy I know was the one putting a new engine in the Mini after that fiasco.