I agree with you that the Tekin motors are pretty good but I have to be honest and tell you that if you have not tried one of the D3 550 motors... You are really missing out! I am running the 4.5 and have a 3.5 and 2.5 on order. The power is great and they run cool just like the 540 version. The 4.5 is already more power than I can put down and the 3.5 and 2.5 are just going to be silly!