$500 over invoice would be a really good deal. but in general, you got the right idea, negotiate from invoice up, not from MSRP down. i would skim through
this thread, there is a LOT of useful info about negotiation strategies.
as far as stick learning, you can read all you want about it, unless you do it and practice it, it means nothing (well, not nothing, but you know what i mean). so as the above suggested, look for a friend with MT and practice. you'll find that BMW clutch is a lot different from japanese cars so that will take you a little getting use to as well. if you want to find out more specifics about how different the clutch is, search these forums for "CDV" (clutch delay valve).
good luck!