I really love the head lights- nice little detail. But with the nutty bright blinding car head lamps we already have, 300 years in the future will probably have pin hole lights that are as bright as a thousand suns.
You should (do what you want), but in my opinion, resist the temptation to go nuts with adding too many exterior details. Just for example, like the grey stripe dealy on each side that apparently visually indicates where the plasma flow goes down to the nacelle (personally this just screams "shoot me here bad guys!")...
Seriously though, one of the problems that happened with Star Trek was the monumental amount of crap that designers started sticking on their ships in an effort to make them look more interesting. Especially on the Runabouts. The panelling detail was crazy for such a small vessel- there were so many lumps on it, you'd swear Starfleet contracted out the Empire to put it together. This is the future, they wouldn't need so many little panels- I mean we presently have HUGE boats that are essentially moulded out with super clean one piece hulls. The original shuttle looked like a clean 2 peice hull.
Just look at the various shuttles in ST:TMP- they looked newer, but were clean looking. And in the movies and TNG for that matter. They still looked okay without being too much...
There's nothing wrong with detail though!!! Just know when to hold back- this vessel is looking great so far- please do get me wrong- I'm more critisizing past Trek designs...