5.0-liter V8, 302 hp. Mercedes SLs have a life span more akin to a giant redwood or a sea turtle than to a car. The SL gets a refresh in 2009 with some meaningful upgrades, like a wet-clutch automatic transmission for the SL63 and beefier motors in the base SL and V8 AMG. But the 2003 model looks much the same, plus featuring a slick retractable hardtop and maintaining plenty of power (302 horses from a 5.0-liter V8, versus 382 hp from a 5.5-liter motor).