Spin buggy? I would have loved this when I was a kid....I still think it's a great toy! Didn't know it existed until your post. Thanks for sharing.
The photo of the box with the two spin buggys in one box is from a current auction on Ebay. More common were the two buggys (T-Square and PitBoss) sold in separate boxes, which are the ones I have. By the way, I have an extra one I can bring you to Miamisburg, if you are interested. At the Nagoya museum I saw a third version that I have not seen anywhere else. One thing most are missing is a rubber band on the right tire, I think to compensate for uneven traction.