Earlier today we posted a batch of SL-Class major facelift spy pics of the AMG models. But moments ago, these more revealing shots landed on our desk. These non-AMG prototypes wearing Michigan plates have hit the Southwestern desert, and have now removed the front-end bra to allow for accurate cooling tests in the sweltering heat. This is our best look yet at the new SL’s CLS- inspired headlights, which sweep up around the front fenders, and the new chiseled front bumper and bold grille design. Tweaked tail-lights, a revised rear bumper, and new exhaust ports round out the changes at the rear.