I don't think Phil needs to explain...........EL SHELBY is 100% correct. "Shelby has, and is, designing and developing their own parts.
Up until *just* recently, that statement would have been more false than true (the, "Shelby HAS" part of your statement).
Just off the top of my head, the only parts I can think of that "Shelby made (or "developed")" prior to recent offerings were the "Super Snake" dash gauge pods, hoods and quarter window scoops. Possibly the SS front splitter but even that may be a more recent exclusive part.
They just recently developed (if you want to call copying the Ford SVT Boss 302 trans cooling scoop 'developing') the transmission cooling scoop, rear shock tower brace and the yet to be released oil separator (also a copy of other products). I may have missed one or two items but in short, VERY little was "made by" Shelby (and yes, I know THEY don't actually mfgr. those parts but they are exclusive to SA).
There are a couple of other more recent parts I'm sure I'm missing but basically, they have been re-badging aftermarket parts and calling them Shelby items. They *did* work closely with Scott Drake but they were still rebadged Drake parts they sold and you could get the same parts from Drake sans Shelby badging.
Recent events actually point to the fact that Shelby didn't design the Super Snake and KR Alcoa wheels! (see the patent pdf file showing Alcoa owns the patent to the design AND mfg. process).