normal as in not the AMG? is the only other option the 550 i think? twin turbo v-8 (402 ho 453 ftlbs) to the A7s supercharged V6 (310hp, 325 ft lb) so MB wins that match; but in turn A7 gets better milage, depends on your priorities. Each is filled to the gills with new electronics i won't even pretend to know about. At that level of new luxury the only way to decide is to take them both out and feel out the controls and dynamics.
gran coupe is very good looking, MB has some strange lines but is never a bad choice but I have a weakness for Audi so i'd probably default that way