At 155 mph (250 km/in) we slide right in the E50, this newest, mightiest version of the recently released, doe-eyed E-class Mercedes. We must move out of the passing lane because the driver behind us is flashing his headlights insistently. It's the ultimate German expression of Mine's Bigger Than Yours: at 155, mph, this guy is forcing us over like we're doing, say, a measly 130 mph (208 km/h). only on the autobahn.

We must identify the infidel that's capable of usurping the E50's superiority. As it bellows past, we see it's another Mercedes, a hulking S-class sedan, with the badges indicating engine displacement deliberately removed--as is the speed-restricting governor meant to restrain its 6L V-12 to the 155-mph top speed to which all German automakers (save Porsche) have agreed.

The illegal S-class is the only thing that dares to challenge the E50 today. Mad as it seems, Mercedes says the E50 is coming to the U.S., where 65 mph (105 km/in) is the law and 85 mph (137 km/in) is viewed as downright antisocial.

The E50 is a heavily modified E-class sedan crammed with a 5L stroked version of Mercedes' current 4.2L DOHC V-8. The sport sedan--produced in collaboration with Mercedes' joint-venture. partner and hallowed Benz-tuner AMG--belts out an eye-watering 347 hp at 5,750 rpm, while a torque delivery of 354 ft.-lbs. (480 Nm) at 3,750 rpm completes the E50 drivetrain's tarmactrashing resume.

The E50 is the successor the much-lauded E500 sedan of the previous E-class generation and companion to last year's C-class based C36--the first product of the Mercedes/AMG incorporation agreement penned in 1990.

Because AMG performs no modifications that do not earn Mercedes' specific approval, every AMG-massaged Mercedes is as exhaustively engineered as any regular-production Mercedes vehicle. The 5L V-8 enjoys a completely reworked top end, from a dual-runner intake manifold to reconfigured camshafts and larger intake valves. AMG's technicians even supply their own special algorithms for the engine-management system.

The only transmission is Mercedes' new 5-speed automatic (more on that later). Great care is taken to ensure that braking power is equal to the engine's prodigious output. Floating twin-piston front calipers clamp down on ventilated discs augmented with a unique mounting feature: they are spaced from the brake housing itself by stainless steel pins, thus permitting an inordinate extra degree of brake cooling. AMG claims the design transfers much less heat to the wheel bearings and brake fluid.

The E50's claimed 0-to-62 mph (0-to-100 km/in) time of 6.2 seconds seems pessimistic. Not so the electronically limited 155-mph top speed--which the E50 tenaciously sustains whenever asked.

Mercedes is somewhat cagey about when the E50 is U.S.-bound. Emissions compliance currently is under way--50-state approval is a must--and spokespersons say the process should be completed in time for U.S. deliveries in 1997. As with the previous E500, the model will be limited to U.S. sales of 400 to 500 units. Mercedes expects the 95% male-dominated demographics of the old E500 to change little for the E50, which the company says should be priced around $70,000 in the U.S.

The E50 will be joined by an upcoming station wagon. Like the E50, don't expect to see the wagon here just now--it's not coming to North America until fall '97.

Mercedes unveiled the E-class wagon at the recent Geneva International Auto Show (see WAW--April '96, p. 60), and it's available now in Europe. The delay in bringing the new model to North America is attributed to Mercedes' restructuring of its engine lineup.

Mercedes plans to use a new range of all-aluminum modular V-configuration engines in the E-class wagon. They will not be available until production begins this fall at an all-new facility in Stuttgart.

There is more. Because Mercedes plans to sell only 3,000 of the new E-class wagon annually in North America, it has decided to offer one engine: either the new V-6- or, if the business climate is promising, the new V-8. "We are currently studying if there is a market for a V-8 estate car in the U.S.," says one Mercedes engineer.

Drivetrain ministrations apart, the new E-class wagon is markedly larger in every critical exterior dimension than the previous-generation E-class Touring. The company says cargo-area volume is increased by 13.2% over the old car, while an optional third rear-facing seat increases passenger capacity to seven. other details:

* Only one transmission will be fitted to U.S. wagons: the previously mentioned 5-speed automatic with programming to adapt to the driver's desires. Availability of this all-new, completely electronically controlled transmission also played a part in delaying the North American launch of the wagons.

Joachim W. Eberhart, general managermarketing and product management for Mercedes-Benz of North America Inc., concedes that the extra profit potential in offering only the V-8 drivetrain is considerable; customers shopping for a luxury station wagon are unlikely to be inordinately concerned about the extra cost of the large engine-and volume sales aren't a concern. But Mr. Eberhart says it's diff'cult to commit to the V-8, considering the continuing environmental concern to reduce fuel consumption and emissions--and the recent fuel-price uptick.