You can buy the tool from Bimmerworld for $99, or you can rent it from them with the purchase of the bushings. KoalaMotorsport used to rent them as well, don't know if they still do. Or you can do it ghetto style and press the bushings in using two 2" NPT pipe caps, a 7/16" threaded rod, and a couple of 7/16" nuts and washers.