A leaked document sent to Mercedes-Benz dealers in the U.S. (PDF) has been obtained by C450 AMG, revealing that the company plans to include CarPlay in select 2016 models beginning with Dec. 1 and Jan. 8 builds. Specifically, CarPlay will be offered on CLA, GLA, and B-Class models either as a standalone $350 package with the Audio 20 sound system or as a no-cost enhancement to the traditional Multimedia Package. E-Class Coupe & Cabriolet, CLS,…