Hehehehe. I am posting late to the discussion, and everyone has great points already

I would say dials, not buttons

1) Dials for throttle sensitivity

2) Dials for suspension stiffness and damping

3) Dials for speed of steering

4) Dials for traction control

5) Dials for turbo boost

If one has two buttons, one wants 3.... or none. I like the feeling of infinitesimal control

Oh and.. the Porsche audio systems... Better have an open space than the crappy systems they have on there