Merc's always been giving their AMG's big ass engines to appease the Yankees

. Something like 70% of their cars (AMG) are sold overseas.
And Deeez' rants hit the nail on the head why most Euro's will never buy an American "performance" machine, a respectful exception made for the 'Vette, which is actually a well tuned machine despite it's stone age technology. Most American performers are heavy, technologically outdated and don't offer the refinement of the competition. They also cost half of what the competition costs, but when you're in the market for a serious car you're not going to cut corners for financial reasons. Most wouldn't, and aren't, anyway. There's also still the little problem that, for Euro standards, most American car makers still seem to think corners aren't important.
Case in point being that GT500. They just bolted a supercharger to a stock 'Stang, gave it some plastic bodykitting and presto!, a "mad and raving" new Mustang. Not exactly. It's just not done to drop 200 extra horsepower in a car and not do anything substantial at all to brakes or suspension.
As a result, most American performers are right back where they started. The '70's. Good looks, good engines and the refinement of a hamburger. The cars are more for bragging rights than for serious drivers.
What you would like to see is one of those big car manufacturers waking up to the 21st century and building a kick ass new American sportscar that does justice to the technological capability of the Yankees. It's not like they can't build quality stuff, for some odd reason in the car market, they don't. They should.