I haven't done a wing install on the Supra, but as someone who's done installs on other cars, everything here is 100% accurate and would definitely follow.Just a word to the wise on the wing install:
Be gentle when tightening the wing to the mounts. Use hand tools like the instructions say. It's a slow process, but both the wing mounts and the wing itself have been known to crack when using power tools (from self-installations and professional installers alike).
I would also recommend getting stainless steel mounting hardware from your local hardware store. The included hardware rusts.
Also, I recommend getting some sealant to place around the holes to prevent water from seeping into the deck lid.