They are generally much less powerful than the Star League designs that replaced them. Basically, all of the ships in those areas were either pre-Star League, fielded by peoples other than the Star League, or were Star League ships that were later upgraded into or replaced by the main Star League WarShips we know from TRO 2750.
The stats they are given in the newer TROs make them more powerful than the Star League WarShips that replaced them.
IMHO, as a point of common sense (mine which many say can be a bit off of course), I think the Star League should have the best fleet out there. Therefore, on my table, they do, and when they upgraded ships, the upgraded ships were better than the originals. My table, my stats, and those are the cards that I use.
I make them available for you all if you want to use them, knowing that they are not canon with what is printed.
And having played space battles with the new BForce...oh yeah...the rules totally...ahem...RULE for playing that game. It is fast, easy, and very very deadly. And very fun.
Just remember to print out a sheet with the firing arcs on it. You will be regretting it if you don't. Trust me...been there...done that...