If the rear set is cast and then cnc'd grade 8 bolts will not matter, the cast metal will fail first. I used ss cap screws (most likely softer than grade5) to mount mine to the frame (the pegs have the bolts provided with the sets) and have never had a problem. I crashed my 04 3 times and the 1098 once, nothing ever snapped, just pegs ground away. Ever snap a pedal on your bicycle, it hurts! I'll stick with what has been proven to work........