Neither - it's firmware. The machinery is the same, but the power and therefore range of the transmitters is governed by what firmware that machinery is running.
You could, but then you'd be flying illegally of course...
TBH you can't see a Q much past 400m anyway, so were you to fly outside that range you'd be breaking the law about Visual Line of Sight as well...
You might be right, but I'd wait for the people who have Q's to confirm that. I'd hesitate to condone it myself I think - probably better to stay legal for the sake of 50 ft - I mean 1200 ft is quite a reasonable way out - I tend to rarely go past about half that, and I always make sure there is LoS between my controller and the craft, so I never get any dropouts. I guess if range is your big thing then DJI are probably the machines for you - their CE models will go a lot further than the mantis.