OMEs (if youget spring and shock) can come pre-assembled from wheelersoffroad. It made installing a snap!! I installed them on my taco a few months ago. Was easy, just need to have the basic tools, jackstands, and your set! It's kind of ghetto though when you follow the customtaco writeup on how to install. You use the stock jack to push the a-arms down so that the shock gets compressed. Worked fine though!