Hey Sona, you might remember me from some of my posts on the Lancers Reactor.
Personally, I think one of the tougher ships is the Nomad Attack Carrier, but I don't think that's buyable anyway...but it is a tough ship. I think I'd side with the nomads on this one if I could.
In the mod I've been working on, my toughest battleship can be cut to shreads by the nomads. (well, parhaps that's because they're using modified Mark03 nomad lasers with a refire rate of 4 each) and the battleship has an armor rating of 3 million with two class 10 shields.
ANYWAY... why not just get the better of the ships rather than try to get them changed? Might work better that way. (Fight fire with fire)
Besides, if you threaten to leave a server, chances are likely someone will hold the door open for you.