eibach arbs are for cars with or without xenons, h&r do a different bar for each for some reason? i have xenons and eibach arbs, also you cant gauge the stock bars in size against the h&r and eibach as the stock bars are hollow, and the eibach and h&r are solid. on the eibach and h&r there are 2 positions, the inner being stiffer. to start with i fitted the rear only on the soft setting and on its own it really improved the roll, but it imediately made the front feel soft, when i fitted the front it sorted things out, i now have the front on the outer soft and the rear on inner firm and it feels great, at the weekend i will be having a bit more of a mess around with the possitions.