1st off i would like to say..its all made of metal and NO PART is bullet proof,the all can and will break..no matter what brand they are.
with this said..i will say most serious blown motors and Nos motors use the aluminum Rod...they tend not the beat the bearings to death.
i personally run Crower Titanium Rods in my 632.
Brian
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Bjuice..
"I'M YOUR HUCKLEBERRY ! "