Size of ship should never limit top speed. The Mass Vs. the Thrust should affect acceleration speeds, breaking speeds (reverse thrust) and turning which it already affects. Maybe they need to be tweaked a bit but, in space, something could technically speed up forever. Of course your pilot would die from the force of it lol.
In space, you don\'t need more POWERFUL engines to reach a \"top speed\" only to reach it quicker.
Also, you can modify the top speed on your server in the server.cfg file. I would suggest NOT putting it above 150km/h. We keep ours at 100 and if a lot of people are zipping through sectors at the same time, it can kill your server. There are also other settings in there to adjust the amount of time a sector stays loaded after it\'s empty etc... Some tweaking could get you higher but 150km/h is REALLY fast in this game. Jump in a tiny fighter with a ton of thrust and it\'s SUPER hard to control with those speeds.
You can also make space really like space... If you bump something it will NOT ever stop until it collides with something. You can edit the config file for this.