Wagenheber....

that´s right. If you have no spare tire, then you also have no ("wagenheber") jack. you can ask your dealer if you can bye an original jack, or you can bye at a hardware store an hydraulic jack. the question is, wich is cheaper.
i hope this helps you.

Depends of if you want to carry it with you, in your car, or just leave it in the garage. In case you want it in your car, I would go for the original one, cause it has it's designated place in the right side of the trunk.

Unfortunately I can't help you with that info. But before I forget: you will need also that special fixing screw (I have no idea if it's sold together with the "Wagenheber" or you have to order it separately)