So, I followed the ideas of a few other forum members and did the 3 inch flange attached to the back of the front caliper along with the flex hose . I put temp strips on the calipers and the ducts worked fine, but after 5 track days they had worn through on the lowest point ( curbs?)....so I am trying a shorter hose strapped to the top of the lower control arm. I will test this shortly....meanwhile I am working on a naca duct design, probably using a 2.5 inch hose