In the mid-1980s, the BMW M 635 CSi and the Alpina B7 Turbo Coupé were the fastest ways to drive a BMW Granturismo. As similar as they were on the outside, they went completely different ways under the hood: four-valve versus turbo technology. Even back then, the automotive world was interested in which was better. This driving report compares the top coupés from BMW and Alpina and shows them in many photos.