Originally posted by: AndyHui
The toys themselves.
Certain changes have been made to the molds for the US versions, and they use plastic parts where they are die-cast on the Japanese version. The JP version is an original Diaclone mold (the line of toys before HASBRO brought Transformers to the US).
Optimus Prime with Apex Armor was never released in the regular line in the US. The others, such as Skywarp, have had their missiles lengthened, while others have had various modifications, such as Prowl's feet/back windows.