toe to toe; Our intelligence network detects a power build-up in Germany-a clash is inevitable.

Byline: GREG KABLE

Famed for engineering prowess, the German auto industry is also rife with rivalries and internecine politics. In plainer terms, it's a competitive snake pit, where accomplishment is measured in engineering terms as much as on the sales floor. That attitude drives the major players to build ever more powerful supercars to prove themselves superior to the other guys. We set our spies to work for this exclusive look at what's being tested. Here's a sneak peak at what is coming up, fast, on the autobahn.

** BMW M6

BMW's 6 Series on steroids, the M6, will make a return to the performance-car ranks after a 16-year hiatus. The new model, caught in prototype form under- going final shakedown tests, makes its public debut at next year's Geneva show, with North American sales planned by this time next year.

The prime targets for BMW's bold new two-door are the recently reworked Porsche 911 Carrera, Mercedes-Benz CLS55 AMG and upcoming Aston Martin DB5. It could set its sights higher up the supercar ladder with power coming from the new M5's extraordinary 40-valve 5.0-liter V10 engine.

The M6 will get 507 hp at 7750 rpm and 384 lb-ft of torque at 6100 rpm-174 hp and 52 lb-ft more than the 6 Series flagship, the 4.4-liter V8-powered 645i. BMW's latest seven-speed SMG (sequential manual gearbox) will be used. The V10 should make the M6 BMW's fastest road car so far: Insiders hint at 0 to 60 mph in 4.5 seconds, a standing quarter-mile time less than 13 seconds and a theoretical top speed close to 180 mph, though like all high-end BMW models these days the M6 will be reined in electronically at 155 mph.

BMW's M division is already looking to go one better. Along with the standard model shown here, it is planning a CSL version of the M6 with lightweight carbon fiber body panels and a more powerful engine to extend its performance.