One of these http://www.ebay.co.uk/itm/Draper-08668-DIY-Extending-Wheel-Nut-Wrench-Brace-1-2-Sq-Drive-for-Car-Caravans-/121137466236?pt=UK_Hand_Tools_Equipment&hash=item1c345b0b7c
is always handy to have & most any car jack will do the job , no need to be BMW specific
There was a thread about jacks a while back. As long as you go low profile you'll be good. I bought a Clarke one on recommendation from other forumites