I guess it all comes down to how much money we have to hang off our rides.
Jay Leno of Tonight Show fame has finally found an engine that should be a natural for beetles. Jay found a guy in LA.(Louisiana) that installs retired Bell Ranger Helicoptor turbines in road bikes and pickups. Don't get to excited though, the price tag on the bike is $150K. The "stock" bike does 9 sec quarters and is good for over 200MPH on the road.
HOWEVER, the 130# turbine puts out between 320 and 350HP @ 450 ftlbs of torque. This should make a nice power to weight ratio for beetles. Downside is 4MPG on diesel. But with acceleration like that, who really checks MPG.
