From what i have seen, if you are doin faster than 54's at Daytona on a 600, ya need a Daytona spec tire... even the fabled UK Dunlop won't work if you are goin fast, if on a 600. Interestingly the lightweight twins, even real strong one and doing 56-55's, can use almost any rear (doesn't need a spec rear). Not getting as abused on the banking. All the current Daytona spec rears are good. Different characteristics from one brand to another, but all good.