You'll gain almost nothing if limited to the oem springs. If its ride height you want to retain I'd recommend finding one of the coil-over kits that can be set for oem height. If it's the softness you want to retain then the GR2 may be your best best. I've heatd repotts that the AGX lack control even though they can be adjusted a lot firmer. A stiff damping with a soft spring isn't god, they should be matched to make it work wrll.