When it comes to dealing with the competition, Mercedes doesn’t generally tend to be in much of a hurry. They remain the elder statesman of the European car market, they remain arguably the most respected voice in automotive design, and they really, really know how to milk a teaser campaign for every drop of media exposure. The company started dropping hints last winter for the 4-door AMG GT models, which will complete the standard production series of the line. This month they finalized pricing.

With the 4-door Porsche Panamera on the market and doing well, Mercedes has finally and definitively followed—after a judicious delay—with a super sedan of their own. The 4-door GT 63 and GT 63 S variations on the theme are coming this year, and are priced right in the sweet spot for their niche.

The cabins emphasize space, of course, and all U.S. deliveries will accommodate four adults very comfortably; an executive backseat option extends the area and adds a touchscreen for chauffeured driving. Driver-tech includes standard dual display screens and interactive controls.

The 4-door models start at $137K for the GT 63 ; the GT 63 S comes with a base price of $160K. The cars are outfitted with mighty powerful V8 engines producing 577 and 630 horsepower, comfortably surpassing the Panamera GTS and Panamera Turbo’s 453 and 550 horsepower, respectively.

Horses are not the end-all be-all, of course, and Porsche’s brand loyalty speaks to its engineering excellence. Nevertheless, Mercedes-AMG’s message to Porsche is very clear: Be afraid. Be very afraid.