Originally, the bigger and more fore of the cowlings was of the lighter hull color, so feel free to play around with that. Also, I'm fairly confident you'll find an excellent bussard color.
And feel free to up the resolution of the nacelles. The panelling lines are very heavy there as opposed to a lot of other places on the ship.
One more thing that occurred to me was that there doesn't seem to be panelling on the saucer rim besides the four horizontal lines. I think some light and subtle panelling behind the windows and those lines will really flesh out the ship.
All this being said, I think that secondary hull might be the most beautiful thing I've laid my eyes on.

EDIT: Yeah, just screwing around with the thread name. Hmm, BS Productions?
