Originally Posted by THE TECH
I don't use it. I don't buy that BMW researched the extra wear on parts either.
I think they have - different starter which is MUCH more beefy than the standard one, and different alternator. There's nothing else really that would be affected by the start/stop feature.
Using mine today - for fun - it turned off exactly where I stopped for my destination. I got out of the car while it was off, took a few things out of the trunk to give to the passenger I was dropping off, and then went back in the car. Put my foot on the clutch, and I got a bling and a message I have never seen before on the iDrive, accompanied by the start stop symbol with "OFF" under it in the cluster. Damn this car is too smart. It works perfectly on my 08 although I never really use it. I do intend on switching the alternator and starter at some point to fully complete the retrofit.
It's also a very voltage sensitive feature. If your battery is not in tip-top shape it won't turn off the engine.