Not arguing, but that seems really extreme. Isn't that really soft in the rear and very hard in the front? I get that the springs stand up in the rear but 125lbs per spring per inch is when the engine alone weighs in at 400lbs. It just seems like the rear would roll in a turn.
you could even go lower in the rear but 125 is pretty amazing. the shocks that come with this car are not even close for optimum suspension. I now get roll in the rear which lets me setup for turns and actually use the sidewalls on my tires. You want roll in the rear as long as your not breaking loose. I am still not pushing in the front with the 600 lbs now the front does have 175 lb keeper springs which absorb bumps pretty well. This setup is the one that George sent me and it handles WAY better than the original setup. I wish I could let you drive this thing once.
The 600# spring is 8" long ( makes it easier to install helper spring) Use Hypercoil HYP18DS100 adapter between main spring and helper. Helper spring is Eibach EIB0175-250-0150. Requires that main spring be compressed to install helper.
Any brand of 2.5x8x600 coilover spring will work.
The rear spring is a QA1 2.5x10x125. It is longer than original to give more consistent spring rate.
PS. you can use the Hypercoil CS100 as the helper spring, it is easier to install.
This setup seems work well but each car is different, and each driver want a different feel so it may not be perfect for every situation.
The reasoning for this setup is to take up the body roll control on the front wheels as the have very little load and not overload the rear in cornering so that they can put power down for acceleration out of the corner.
under hard driving at an auto-x event we were able to get the front to push. for how I drive I like the rear setting but might soften the front a little. we also had an issue with locking the front brakes up under hard braking.
All this being said I feel we also need to fine tune the ride height, camber adjustments and the rear tow in. we took a shot in the dark on these and I am sure with some tweaking each can be better setup. I will measure everything and do a write-up then start making adjustments. a few more events and we will have this thing dialed in.