I understand that it will burn eventually, but coils are only five bucks per 5 and it tastes great on 4.3v so it's no biggie. I know that spinners can do that, but I've read somewhere that it's better not to with fakes.
Edit: I just tried to tune it anyway, but it seems that even if you twist a little bit back from 4.3v it just gives same power as it would be set on 3.8v.