I am almost finished going this route. Run a search on the GL forum on
www.shoptalkforums.com. I would rather not write it all up again. The rear is easier with the Porsche calipers as they just bolt on. The front is about as difficult either way. The adapter being the big problem. I have a two piece design which is adaptable for either caliper with minimum machine work. The problem is all the different ways that it can be done and all the different parts you might use. I may eventually decide to make a kit. Anyway you look at it, it still would not be cheap. The Wilwood calipers are not DOT approved. Hope it helps.