Under normal driving condictions hitting big potholes in the 2 years so far and everyday driving not once have they fallen out and I now have them on my swift gti mini and it's pumping out good power and same thing again no problems.
The comfort over cOnes is so good, its better then cones.
They only way it could dislodge or does is when you jack up the car really high and let the bottom arm be disconnected from thr shock leavibg it at full droop it will be loose.
So there is no way that will happen while driving, i hAve hit massive pot holes and no drama.
One thing i don't miss is the teeth clenchng when coming unto a big bump train tracks or a expansion joint in the road.
I'm just giving a honest opinion, I'm sure they can fall out but I have never see it happen witht he mini tastic kit, it's the only kit mini magazine say to fit.
I have seen problems with other springs though cracking subframes etc.
One thing I can say once you fit springs you will newer ever ever go back to cones.
I would go the fast road kit, if you like the car really high and drive like miss daisey get the town ride kit.
Like anything there is a risk as the lads have said but lots of people have had not one problem. For one problem there is many that have been fine.
It's like saying the a series is crap and blows up all the time and is
Un reliable.
Well it's not, if set up incorrectly it could be. Set it up right it will be fine.
One disadvantage is on the rear you can get some body role, it really pends what you want? If you are racing stick in some yellow or red cones.

Good luck. Let me know if you get the springs