I'm only saying that you can't remove the thrusters and may (should) remove the shields because I have personal experience with both things. I've practiced without shields and without thrusters (though this last one was more of a goof around). You take the shields away and the fight get VERY interesting. There's no relying on shields for a head on, you have to preserve your ship to the last bolt, every landed shot counts. Really, it's awesome.
No thrusters is like... Meh. The fight gets slow and very predictable, there's little to none room for evasive tactics and aim... well, the ship is moving so slow it's rather idiotic a task for anyone to aim without thrusters. If the ships are exactly the same it may even get ridiculous depending on the stance of the fighters, they may end up chasing each other's tail endlessly.