few observations:
i modify jump and walk speed only. so when i run, other players don't see i'm cheating. when noone around, i just press Z and hunt mobs.
about jump and cast range... I set jump to 50. find an agro mob, stand far away from him, so that he doesn't see me and he is out of range of my spells. I jump forward, landing near him. he doesn't see me, in a second I warp back. mob doesn't see me, i can't shoot him. ok. I jump again, land near him, shoot and actually hit him, and warp back, mob runs to me, i can't shoot again till he is in range again.
what does this tell me? mob's AI is server-side, that's for sure. so when I see myself landing near mob, uf I truly was near him, he would attack. thus, what I see is not what it looks like on the server side. but I can shoot, as if I truly was near him...
=> range (and probably visibility) is determined on the client side. jM3, did you see anywhere in the code this range comparison?
note:
if you want to repeat this, do not press constantly fire button. wait until your char lands, then press your spell shortcut. you'll probably warp before cast animation plays. no matter, spell-ball will fly from the location you warped to.
edit:
not sure... managed to repeat this 3 times only.