Man! I really like this design! Looks like it could fit right into a TOS episode.
Far too often, new designs for TOS era venture into near 24th century technology.
I, for one, never really cared for the Bird of Prey (at least for the TOS movies). Something like you designed would have been much better -- with maybe some plating added to keep it consistent with the K'Tinga class battle cruisers.
Again, great job!
If there's one thing Steve Cole can do(apart from design and manage an awesome game with incredible longevity), it's design ships that look like they belong in the TOS era.

His design sense is completely unfettered by "kewlness", which is why a lot of Star Trek fans don't like SFB ships. And it's also why I try to make the same SFB ships look good in my renderings without resorting to J.J. Abrams-style weird redesigning; to prove that the TOS era can look good(plus SVC wouldn't let me redesign his stuff even if I wanted to).
This ship would nicely fill the role that the Klingon Bird of Prey was meant to fill. No cloaking device(SFB klingons don't cloak), but a small, fast, dangerous ship. It would have been nice to see something akin to this in the movies and TV shows instead of a misappropriated Romulan design.
Anyway, thanks everyone!