^ they work awesome and super easy to install with the bmw shocks . I did put 1 o-ring on each side to stop the spring from sliding all the time, just make sure the o-rings are not to thick or else when you close the hatch the lights at the back of the hatch will stay on,thats what happened to me I was using 2 0-rings on each side and had to take 1 out,now is all good.
anyway heres the link where I got mine from.
BMW X5 E53 Automatic Opening Trunk | eBay
oops talking about 2 different things ,but these are sweet too.