I think the lower control arms are included in the winter special. I know they were when I got my kit many moons ago. Even if you are unable to take advantage of that deal, it is well worth it. I could not see using the donor arms (clunky and bulky) when you consider how clean looking the rest of the chassis looks. There might be some improved geometry but I decided basically on the clean elegant racing look. I guess that's a little shallow but if you can utilize a better assortment of wheels there's a real practical reason to support your decision. WEK.