When your car modification involves creating a special sliding roof so that the exhaust from your rear-mounted jet engine can burp fire, you reached the carbuilder's Valhalla. Meet the Mini Jet, a 650-hp, dual-engined rocket.

Constructed by BMP Design of Tyler, Texas, the Mini Jet mixes a tuned Mini Cooper S with a Rolls Royce-Allison 250-C20B turbine engine behind the front seats, adding 420 hp and 400 ft-lb. of torque driving the rear wheels. The roof modification — an electric shutter and fan — was necessary to port the exhaust from the turbine while protecting it from rain, the only Kryptonite that could kill this Supermini.

As the video below shows, each engine requires a separate fuel tank, so the throttle for the jet engine is a stick on the side of the driver's seat, just as it was in the helicopter where the turbine came from.

The builders say they're working on the car for an unnamed "client." Who could have enough spare cabbage, a fascination with jet-powered vehicles and a history of owning rear-engined subcompacts to order such a contraption?

Thanks Dan!