With BMW manual trans. it is almost effortless shifting, like it wants to go into gear. I learned to drive stick in Vermont, which topographically looks like the Himalayas. Great for snowboarding, bad for learning stick.. Long story short I didn't drive stick again for over 2 years. When I picked up my car last month I literally jumped in and took off, the only thing (which my sales person pointed out) reverse is all the way to the left and up with a slight resistance. There is a good explanation of reverse in the owners manual (which just so happens to be posted
http://www.e90post.com/forums/showthread.php?t=29803.) Depending on the size of the dealership you could always make a loop or two around the parking lot to get familiar again. Its like riding a bike, you never forget, just take it easy, nice fluid movement with the clutch at you should be turning laps with BMW-M WTCC team.