I've got a thor on my omen. It is a little on the heavy side, but i don't even notice the weight difference. I am running a Pure Energy 45/4500. If you read the Omen manual, it says the input pressure should be between 300 and 500. Just be careful getting too much higher than that.
Omen  (Silver Trigger) - Omen  (Black Trigger)
Toxic Matrix - Evil Pimp - MacDev Cyborg - AKA Excalibur - AKA FL Viking