So far im not impressed with the strong arm kit, it left permanent marks in my phantom arms and in general you can feel that something is loose when you apply minimal force to the arms, it was much better without them. But i will give those strong arms plates another chance, the owner told me that he will send me a new kit to me because my old kit was pretty roughly done according to him. The bottom side is rougher than usual. I will wait with my final conclusion about these but i have now a Phantom3 with bite marks in every arm