The script itself is perfectly stable.

As for the effects of raising max speed:

Depends whether you're talking singleplayer or multiplayer.
SP it's perfectly fine if your processor can handle it, generally.
For MP it's gonna depend on the server sim and the state of the netcode, as well as how good your processor is...

As far as collisions go, large ships should be fine as long as they aren't in the high thousands. At that point you will probably notice a few seconds of clipping before things catch up.
Small ships will probably hit the bullet-through-paper collision issue at times.

My server runs 128/256 to be the most stable while allowing fighters to be+feel fast :P

Any experience on how stable this runs regarding physics?

Thanks for doing this!