So, thinking about doing some nylon and see that the higher required extruder temps are harmful to the PTFE lined extruders like in my Qidi X One and Klic N Print 3D. So I was thinking of upgrading one extruder... maybe one of the 2 in the KnP, to an all metal hot end. I see several offered, like the E3D v6 that look promising but I have no idea if it would fit in my printers. Are these things sort of universal? How does one go about determining what fits and what doesn't?