BMW 7 Series

Thanks for reply, but if you don't mind, what about 735i?

It really depends more on your driving habits, and your ability to maintain the vehicle(diy or ability to pay someone else). Technically the smaller engine should be better but a 7 series(not sure what year you are talking) are generally heavy cruisers and an underpowered engine might make you need to rev it more to get going versus having the torque to ease into accelerating. Transmission also comes into play using mechanical advantage to make up for less power.