Not necessary unless you are aiming higher than 340 - 350 rwkw with a good tune. I have run stock pistons with 343 rwkw and no problems, they only started to suffer after I pushed it to 360 rwkw, and then not even dramatically, just have a broken ring land or piston ring, but obviously need to be fixed. ← Agreed, but allot of the time people wouldnt bother changing the rods unless they were going 340rwkw +, if your not planning to go over this power level the standard rods will not need to be replaced. Jet