Hi again,
This is what my snap-in cup holders look like. They are held in place by three little pegs, one of which is spring loaded and can be depressed with a button. The pegs lock into three small holes in the side of the vent moulding. My Carrera is a european MY99. I don't know if all cars have these molding but if so, you'll find them by the arrows in second picture.
Pic 1, in place:
Pic 2, folded:
These holders don't obscure any instruments or controls and IF you should spill your drink it ends up on the floor, or at worst on you knee, instead of in you radio/AirCon/PCM!
I don't know if these are available in the US, but i bought them at my local P-dealership here in Stockholm.