the inline is smoother than a V, it is more naturally balanced. Companies only do Vs for packaging, or for costs. It is cheaper because companies can do a "modular" concept, like Mercedes has done. Since '97 they have gone away from the inline and to the V6, because it makes it cheaper for them overall with their V8 program. That being said, I'm taking delivery of a new MB next week, with a V6. I like the car, but would like it better if it had an inline 6. The MB V6 is definately a notch down in terms of smoothness compared to the BMW inline 6, in my opinion.