I bought an '06 GT with 18" Wheel/Tire. If I'm not mistaken, they did some mods from the factory on the spring rates/shock valving with this option. I am not sure I want to install lowering springs at this point as I like the ride height. (Bumper sure clears curbs!). I would, however, like to upgrade my shocks/struts as I feel that the valving is a bit on the loose side, particularly on the rebound side. Compression valving is very stiff though. Has anyone installed aftermarket shocks/struts with stock springs? I would be interested in knowing what brand you used and the results. I have checked around and there are very few units currently available. Most are engineeered to be used with lowering springs. Unavailable as yet are Koni, Bilstein, KYB, etc. Any thoughts here?