The Smooth a Ride cones MiniSport sells are really quite good and definitely improve the ride quality. But I agree it's probably down to the cones on your car have gotten old and hard and need replacing.
I put the black springs on my Clubman estate and thought they improved the ride somewhat, but had the problem Nick illustrates - bent adjuster bolts. I put it down to cheap bolts tho and went with some stronger ones, never had an issue after that over 20K miles.
One thing I never understood is why they designed the Mini with so little suspension travel....handling was NOT the first consideration when they went with the rubber cones but was a happy side benefit - but at the expense of ride quality. There's room for an 8-12" long spring in the back, and at least twice the length of the cones in the front. Seems like someone would have developed a kit by now with longer springs to give more travel and a better ride......
Edited by Magneto, 21 September 2018 - 10:32 PM.