10mm driveshaft strength?

Im doing a ton of upgrades... Rpm trans..rear..etc...took the driveshaft out of torque tube to find broken couplers..(glad i did)
Im goin w rpm couplers 10mm cause my shaft is 10mm 2003
Being an AUTO im wondering if the 10mm bolts can handle the big power or do i need to find a 12mm shaft?

