@storm
Thats ok buddy 
Now look at the prices of the two cars. S55 is more luxurious and branded - about 120k USD
GT - looks wierd (to me) and is 140k USD !
I am unaware of hp & torque factors; but with 150k in my pocket left aside for purchasing ( a ) vehicle(s) only, Id get a S55 definately choosing between these 2!
And now in 2007, you can get a S63 AMG in 128k with
"Truly moving. Passionate performance comes sharply into focus with a thundering 518-horsepower, V-8 AMG engine, F1-inspired manual shifters, the rush of race-bred brakes married to 20-inch AMG 5-spoke light alloy wheels, responsive 7-speed automatic transmission, and AMG-calibrated Active Body Control (ABC).$127,775*AMG hand-built 6.3L DOHC 32-valve V-8 - 518 hp @ 6,800 rpm
You dont have to be a fan of MB, like Im a fan of no one n no thing! Make others your fan 
Itll be hard for me to do that here as you are all 2 times my age; but in school - mission accomplished!