Printing Nylon

So if I just put on the e3d head I will be able to print nylon with no other upgrades or changes? Can the gmax get to temps high enough to print Peek with just changing the head?
To print PEEK you will need to install a temperature sensor capable of accurately reading temperatures that high(350C). There are probably other modifications necessary but I have not looked into it. We have not done any testing in this temperature range. Modifying the gMax to print PEEK will void the warranty.
Kyle is right about the temp sensor you'll need to use to print with PEEK and PC (PolyCarbonate) as they get above 300C and at that point you would need to use a thermocouple as your temp sensor. My first upgrade to my gMax 1.0 was to get dual E3D hot-ends for materials like Nylon and TPU (i.e. NinjaFlex); and they also sell the thermocouple sensor and wiring:

Although if you get their new cartridge hot-end this would be a better sensor:

I don't know of anyone on the forum who has actually setup a thermocouple and tried printing high temp materials but I could be wrong. I just haven't bought the pieces to do my own heated glass bed for my modded gMax 1.0 but once I do the next goal is to finally install the thermocouple and try working with PolyCarbonate and eventually working toward PEEK.
I am starting to print with polycarbonate right now.. PCplus from polymaker.
I print that at 285 on the e3d and it works just fine.
I havent gone higher, and wont :)