Well i don't know the exact figures for the Eibach,(it too is two way adjustable, and i have it on the stiffest setting) I think TB said earlier that the Whiteline is 144% stiffer compared to stock? It's not enough to judge an ARB by the Ø, some are hollow some are not, some are made from harder/stiffer steel then others..
I do know my 3.2 is more then enough light at the rear with the eibach and KW II suspension, especially in off camber corners. This is the reason why i opted to add camber. (don't know yet if it worked) When pushed in relative flat corners, the car did slide quite nicely over all four wheels as it was (Ie.very forgiving) so I hope i didnt upset this balance too much.
It's too much of a bother (for me) to adjust the rear ARB before a track day, so it has to work for every day use.
One thing which you mught consider, and that is, that the Whiteline is made for the 147 GTA, not the 156 GTA. The 147 GTA rolls ALOT more in stock form then the 156 GTA does. I think this is caused by it's shorter wheel base and higher point og gravity. The 147 GTA grips very well though. From what i have experienced, the 147 does understeer more then a 156 (not helped by the VDC constantly keeping it in line)
Bottom line is that I personally don't think the Whiteline is something i would want on my everyday car, it's a bit too hard core I suspect. but i'd certainly fit it if i start stripping out the car making it more track oriented, or if i had a beast like TB's car.
