More detailed spy photos of the long-rumored Mercedes Gullwing sportscar have broken cover, courtesy of admirably nutty Brit car site PistonHeads.  This replacement for the soon-departed Mercedes-Benz SLR McLaren will feature "gullwing" doors in honor of the famous 1950's 300SL Gullwing race car, with retrofuturistic styling to match.  Underneath, though, the SLS AMG will be a fully modern performance vehicle. The press release cleverly disguised as spy photos tell us a bit about what to expect from the SLS.  The chassis is an all-aluminum space frame, for exceptional rigidity and reduced weight.  Power will come from a front-mounted aluminum V8 sitting mostly behind the front axle.  Based on the bespoke AMG 6.2L 32v V8 that sees duty in everything from the C-Class to the SL,