I put 3rd party guards on my p3, I noted the screw length, but all I did was turn the motor after the gaurs was installed. I figured if the screws were into the motor, I could feel it. My issue was the angle of the motors. Even before I put the prop guards on, I noticed all four motors are slightly cockeyed, the don't all point straight up. And they were the same after installation. I went online and looked at every picture I could find of a p3, p3a, and p3p, and none of them looked cockeyed. Is this a design thing? I'm no expert, and don't know about prop wash and vortexes and things, but wouldn't it be more efficient to have them all pointing in the same direction? It flies great, holds position, gains altitude, everything. The only difference I can see is coming down, if youre too fast it now has a wobble, like its a leaf floating down from a tree. So I just take it easy when decending.