Same as the above post, I noticed that some of the scarab variants, particularly the autopulse variant are a bit unbalanced, with their mix of extremely powerful shields and good engines they can take on just about anything. I was playing the mod compilation released by DeathSG, so if that's an issue specific to the compilation disregard.
Other than balance issues you've done a fantastic job, the ships fit in quite well with the styles already in game, and they certainly do a great job of rounding out the existing fleets some. Particularly a fan of the Tipi, the game's lack of a dedicated carrier other than the astral kind of bugged me, and this thing makes a nice alternative to the converted freighter.
On a final note, (dunno if you're taking requests) it'd be nice to see a buffalo conversion variant with direct fire weaponry and a bit more hull strength or perhaps a directional field gen. I can't imagine the pirates would rip all those parts out to make a 'destroyer' class ship with the only result being the Buffalo Mk. 2, that thing's a deathtrap.
