I READ SOMEWHERE THAT THE S5 GEARS ARE HARDENED? IS THAT CORRECT? IF SO, ARE THE ROTOR GEAR HARDENED?

CAN YOU USE S4 ROTORS ON S5 GEARS?, OR ARE THE S4 ROTORS NOT HARDENED? AND WHAT IS THE RPM RANGE BETWEEN THE S4 THRU S5

 

s6 gears are hardend and multi window , also have a bigger thrust bearing but are expencive and on back order right now. the rx8 gears are also hardend multi window large thrust area and a whole lot cheaper and avalible, just no o ring groove so you need to sylicone it in place. and yes you can use all of the above on any 13b

 

S5 is hardened as well