Heres my thoughts....if it would have done any good and been structurally sound shelby would have done it already. I mean the man redesigned the complete suspention geometry by drilling a few holes and adjusting the alignment and ford couldnt figure that out.
It was a Ford engineer that developed the Shelby drop, not Carroll. His name was Klaus Arning and he passed it on to Shelby. Ford did not think it was cost effective.
Just about everything Shelby got credit for on the mustang's was designed by Pete Brock including the Daytona coupe.
The really dumb thing is, why didn't Shelby (Arning) have enough sense to use a wedge between the upper balljoint and the control arm, on the R-models, to keep the ball joints from binding?
Street Shelbys got a 1-inch drop which had no binding issues, but R-models got 1¼" drop, which did cause binding issues. -A simple wedge would have eliminated this problem.