Powered by a supercharged 4.2-liter V8 engine, the MTM RS4 adds another 120 bhp (this means 535 hp) and 96 lb-ft of torque to the standard performance of the Audi RS4. And is priced at 20,000 euro, or nearly $25,600.

The engine conversion uses a variation of the ultra-efficient Swedish-made Lysholm Technologies Twin Screw Compressor. Boosting at just 5.8 psi, this is a bolt-on conversion that does not require the engine's compression ratio to be lowered. Cooling arrangements are similarly efficient with a Swedish-made Laminova intercooler providing the charge-air temperature control. This is a self-contained water-cooled system built into the intake manifold between the supercharger and cylinder heads.

The MTM RS4 makes the 0 to 60 mph sprint in just 3.9 seconds and a top speed of 199 mph (the fastest street-legal four-door Audi currently in production).