I think inline 6's will always remain at least a base option from BMW..... they are relatively reliable (except the M3's), have a strong, broad, smooth power band which V configurations don't have (V6s and V8s tend to loose their ability to breathe above 5000 rpm), and are quite economical.

I do believe that the horsepower war can continue with the advent of more hybrid availability...... Toyota plans to offer hybrid versions of all of their Lexus vehicles and many more Toyotas in the next 5 or so years. Honda is getting into the hybrid groove as well. I also belive that will revolutionize the industry and basically force the hand of every one else to produce hybrids for more than just their econoboxes or family sedans. We will eventually be looking at V8 performance with V6 economy, and V6 performance with 4 cylinder economy.