OK - They;re not "Superbikes" but at the time, they were the closest we could get! I've also had the old GPz as well as a KZ550...those bikes were everywhere when I was a teenager.
Here was my '82 GPZ.
In the early 90's I bought a 550 Zephy for the nostalgia, and made a small project out of it...It turned-out well after binning the round headlight for square one, adding a fairing, and getting rid of all the chrome bits, rear fender and stuff. Kerker header, K&N Filter & jetting helped, and radial tires make a difference in the handling...obligatory Lawson stripes for the lengend!...