I have a Sumo and as you know it comes with an ejection pistion instead of nomex chute protector and the same goes for my PML kit. I had a Sumo previously until it took a core sample on its second flight. Ouch. I would like to build this kit stock with the piston. I still have the one from the previous kit and fits great. I sanded and primered it. For those of you who used piston ejection do you primer the piston or just leave the card board finish? I felt if I primered it, it would provide protection and a smoother surface so it fits and slides out better. On PML kit I assume it best to leave it in Its natural condition. Not unless there's a better way??