www.edmunds.com There will be no Camaro vs. Mustang death match this week due to a distinct lack of Camaro, so can we interest you instead in a muscle-car comparison test? Here we have two classic nameplates, each with a 400-horsepower V8 stuffed into a smallish four-door body shell and powering only the rear wheels. Naturally we’re referring to those two paragons of modern muscle, the 2008 BMW M3 Sedan and the 2008 Mercedes-Benz C63 AMG. Don’t be confused by the German nameplates, the aura …