I've got a huge selection of H&R as well as our in house ECS Spacer
HERE on our site for your E53 X5. Do you know what size spacer you are looking for yet? If not
HERE is a pdf which explains how to measure for spacers. Also keep in mind when using spacers you will also need longer wheel bolts, we've made figuring out what you need easy with our Spacer and Wheel Bolt kits.
ECS Tuning