The Flashforge has a firmware limit of 280C using Sailfish firmware (which is probably what yours is running). I imagine the hotend can withstand higher temperatures, but it's difficult to make the flashforge go past its maximum of 280C. It does allow printing faster so long as your filament can handle higher temps. I bought my aluminum carriage from http://shop.raffle.ch/shop/alucarriage-dual/ . It's expensive, but worth it if you want to print polycarbonate or nylon.