Porsche Cayenne Turbo S is one of the fastest SUVs out there. Volkswagen Transporter on the other hand is known for its good cargo space and reliability.
German tuner TH Automobile put a twin-turbo 3.6-liter flat-six from the 996 GT2 into VW Transporter making it just as fast as the Cayenne Turbo S.
This engine produces 560 horsepower and takes the TH2 Transporter from 0-100 km/h (0-62 mph) in just 4.8 seconds. Top speed is 280 km/h (173 mph). These numbers are same as on the Cayenne Turbo S.
Downside is that it is not much cheaper than the Cayenne Turbo S. TH Automobile will build you one for 113,000 euros. Surely not cheap, but you can be sure you would have one of the fastest VW Transporters in the world.