That would not be a good idea on a S2! Take a look at the suspension steup, and it will all become obvious why you cant take it off...what you could do is change to a S1 or RS1600i setup, or do stuff like alter the track width front and rear, camber and castor - this also affects steering characteristics.

Understeer on FWD is normal, and preferable to oversteer. Youd be better off investing in adjustable rose jointed kit, so you can accurately dial in your geometry and experiment to find what best suits your driving style.