I can only recommend what I have experience with so far. I have owned both Bilstein PSS coil overs, and the H&R RSS clubsport coil overs on 2 separate st's. Both were excellent, and didn't ruin the tail happy spirit of the st. The latter offering is much more stiff & aggressive (500 lb springs at all 4 corners). From what I have heard, the front sway bar is pretty involved as far as installation (must lower the front sub frame), and the rear sway bar actually reduces the lift over steer. I haven't dabbled in either, because I very much enjoy the way it goes around corners as is.