MDC is one of the best! The biggest problem with a towbar is that it is a different kind of receiver than what you'd normally get in America, so no cheap way to hang a bike rack or something off it. But otherwise, it's really solid!
It would seem that a cheaper and more efficient way might be to simply remove the crash bar and take it to a welder to have one made up similar to the one that Smart Car Universe have for the 451. I posted a pic of mine earlier in the thread. That's what I plan on doing if I purchase a 453 cabrio latter this year.. Or take a curt or u-haul hitch for a 451 and have it adapted to the length and bolt positions found on the 453 (again using the existing crash bar for a template. Both solutions mean you would probability have to cut into the rear end plastics for the hitch to usable.