all metal hot ends - nylon

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?

you could simply change the ptfe tube for a metal tube. Job done :-)

Most nylon will print at 250ish anyway

Nylon is a real bastard to print with - so good luck :-)