Porsche 550 Spyder + VW Diesel?

Hi, folks. Noob, here.   Just bought a Thunder Ranch 550 Spyder & had a bad idea (my favorite kind):

Can you install a modern VW diesel engine (ala Top Gear's "Project Sipster")?  In a 550?  Has anyone tried?

I'm aware of the many reasons NOT to do it, but is it POSSIBLE?  A 1300 lb car + a motor that pulls 40MPGs in a 3000 lb Jetta has to be good for at least decent gas mileage, right?  If a watercooled Sube WRX engine, will work, why not a diesel?  Tom @ Thunder Ranch told me it could be done... with a little creativity in the motor mounts/half shafts dept.  

I'm no mechanic so I reserve the right to be wrong about everything.

But if If anyone can, I'm hiring :-)