Hi Michael and Geoff,
you're both quite right, I also have had a couple of cars lowered by cutting the springs, and the ride is much harder. This was all the rage in Queensland when the ink on my license was fresh, even though it wrecked the ride of the (street) car by any sensible standards. It was a cheap modification you could do to have your car stand out and look a bit different, hence the appeal at the time!
I didn't explain fully what I was doing, but the reason I had to cut is so that I could have room to loosen the nuts holding the spring on, and therefore create a softer setting. The nuts were right at the end of the rod, and it took quite a bit of compression just to get them on.
So although the spring in question is now shorter, it has (almost) the same length of travel, and therefore is much softer overall, and has room to adjust in both directions. Total force to move the valve is now about the 180g mark. Still a little high, but much closer to where it should be. I mistyped on my earlier post, it was originally 400g! The "textbook" figure is 100g.
Regards
Luke