These shafts and cups are fantastic. Not much else to say. If you are running a big bore this isn't something you "should" do it's something you MUST do. I turned the stock shafts into pretzels and broke pins like twigs (not even landing on power, just the torque). Ever since I put the FLM kit in not one single issue at all. Have had them in now for 15-20 tanks, no lost pins, no pretzels and it puts the power down.