It was a pretty easy to do the control arms swap on my '03 Sport suspension. While you're down there, might as well do the control arm bushings as well as the control arms and sway-bar end links. ECS Tuning has some nice suspension kits that include all the new bits, and the one I put in was all Meyle HD. This is the kit I installed last summer with no issues:
http://www.ecstuning.com/BMW-Z4-2.5i...its/ES2219687/
PS: If you don't already have a pickle fork, make sure you have one before starting the project. You'll still need to separate the front ball joint from the spindle and that makes it SO much easier. Just a couple whacks with a BFH, and that's all she wrote.