Originally Posted by Benito Malito
I dislike the soft turn-in of the Hyperco (due to the progressive style spring) RM is crisper and has a stiffer rate that I feel matches the AGX better.
After using Hypercoil springs on my B14 for years, I dislike them for the exact reason, soft turn-in which leads to an undesired exponential increase in spring rate making it more difficult to handle the car.
If you only care about riding smooth, then by all means, choose Hypercoil. If anything else, I would use and recommend Road Magnet time and time again.