Tyson's best was probably 86-88, afterwards is when he started going downhill when Rooney and the crew were ousted and King took over. He showed his chin in 89 though, when he took the flush shots from Bruno before stopping him mid-rounds. It was that fight that his head movement started being used less effectively.
89, ummm Evander Holyfield, Honestly when I watch his fights with Qawi and his fight with Dokes he was the total package he could box, brawl counter he had it all speed power reflexes. Though I really wish we saw the two fight in 91 I still think Evander would have won it but it would have been much more than what we got in 96