I don’t actually keep a spare kit in the car but I’ve bookmarked this one just in case:
https://www.amazon.com/dp/B004PX8BC2..._g5RTEb50JV3NK
No clue though if it’ll actually fit underneath. Luckily I don’t drive far with the Z and if I do, it’s usually to/from track where I know I’ll have some friends nearby.
For home duty, I use an Arcan 3T from Costco. It’s low enough to get underneath the Z but goes up enough to work on my wife’s X3. They go on sale every once in a while but I think I got mine for $99 (currently $120).
FWIW unless you can get a really long one that reaches the center jack point underneath the car, I don’t think it’s worth paying a huge premium other than weight if you plan on lugging it to the track.