Drop Kicks and Classics use the same shell, but the Booter uses the wider 'lasted' shell. The Drop Kick and Classic use the 99mm last, whilst the Booter features a 102mm last. The Booter also flexes softer than the Drop Kick and the Classic, the Booter has the FT 4 flex and the Drop Kick and the Classic are rated as a 6 flex by the FT flex rating system. The only differnce between the Drop Kick and the Classic is the boot board, the Classic features the rigid boot board and the Drop Kick has the active boot board. I don't ski in FTs but the general concencus from most of the guys that do is that the active boot board is a must have for park riding.