It's possible this refers to the Turbo Tiger prototype which was built back in the 1970's. It had a 200HP turbocharged engine and a retractable nose gear. After the aircraft was tested, the unique engine mount/nose gear assembly was removed and the aircraft remanufactured and sold as a standard AA-5B Tiger (I think either Ken Blackman at Air Mods NW or Loyd Montague at True Flight Aerospace knows the N-number). Last I heard, the engine mount/gear assembly was hanging on the wall at what was Jon Maestre's shop in Brookville OH (which since Jon's death over ten years ago was taken over by others), but I don't know if it's still there.
And if that's not the AA-5C prototype to which they are referring, I can't imagine what it is. I have reason to believe True Flight Aerospace (the current type certificate holder) is doing some planning for an uprated (and maybe stretched) Tiger with a 200-230HP engine, but I don't think that's any more than some back-of-the-envelope sketches -- not even in the blueprint stage.