I'm assuming its the feature we don't have in the US, where the engine is turned of when the car is stopped and out of gear. The engine starts as soon as you push the clutch in to go into gear. Its standard on European cars I think and is a little disconcerting the first time it happens to you. We had it on the MINI we hired in the UK last summer. Its another thing which defaults to on everytime you start up.

 

You don't have any more power on tap when in sport mode.

 

What I have found is I am not as smooth shifting with sport button off. Unless I drive with it off for a long while.

It's just a muscle memory timing thing I guess. so when I realize I am not shifting smooth I poke the button and grin.

 

My '11 isn't broken in yet, but on my '10 MC I was surprised to find I was actually getting slightly better gas mileage (actual calculated, not from the OBC) with the Sport button on than off... Assume it had to do with having better control over the throttle and less lag when accelerating with it on.

 

That could be true for a manual tranny - unless you also don't shift to 6th gear on the freeway like the auto trannys........