Gates should definitely have some kind of texture in the gate itself, like portals in minecraft. But this is starmade, so it should be more futuristic. Maybe it could be a slightly glowing, very light and luminescent blue? It should be see-through though, because otherwise players won't see what they are fly into.
As for the warp modules, I'm thinking they should look nice when tiled (because they will be used in large numbers). I think hey should be bluish, with a blue glow around it, so people can make special warp rooms. Maybe they could have a nice animation? Something pulsing purhaps, to simulate their short but spectacular task. It could be a very distinctive (perhaps purple) circle originating from the middle of the block and then rapidly going to the outside of the block, with a pause in-between the pulses.