With the older Flashforge firmware you can heat up to 260, but there's also custom builds that go higher. We've had great results printing Polycarbonate at 260, just don't try to push speeds too much. I don't know if I'd want to heat a largely plastic carriage machine any higher than that as I've read about warping and melting issues, but we've been fine printing at 260.

-Joe

Access 3D Services Fine Detail 3D Printing by Joe Eckert, on Flickr