i actually have a trinity stage iv head and my bike does run cooler , the diffrence that i saw between the pro design and trinity is the trinity head has little ears and diverts the water around the piston insted of straight thru like the pro design.and you can still change the domes out,my buddy just came back from SA he was ther for aboth 6 mo,what part are you from,he said that he was in jobooty sorry if it's missed spelled i live in california,