Dunno, I have a class 88 CV that's within T4 that would probably crash a server if it was ever spawned.
Probably not, class 50 makes game run at 30 fps on 'Best' graphics preset and 3 class 5 CVs make game run at 20 fps, so the only thing it would do is improve the performance if people won't spawn tons of ships.
Depends on the hardware hosting, and the others playing. I am all for less restrictions on a server, but if you got 20+ players, and all are flying these massive ships, it may cause lag/crashes.... Time will tell, I guess.