I have to agree with MacThule on both points. This ships has a nice sleek look to it. I especially like what you did with the engine glow effect.
I do have to agree with MacThules second point. The fact that it only has missiles and no AMC's can easily make it useless against a same sized ship with a few PD turrets on it. I suggest you make an upgrade and outclass the competition by keeping the ion missiles and replacing the other missile with penetrating or explosive AMC's. Or you could make the AMC's ionic and the missiles explosive.
Also it wouldn't hurt to add a 1 block tall low profile PD turret to the dorsal and ventral sides of the ship. That would give it a much stronger chance of survival. There is a turret pack on SMD of several PD turrets, one or two of which are 1 block tall and all are rapid fire. If you do decide to add PD turrets, I suggest one or two of the 1 block tall ones so that you still maintain that fast and sleek look.