Basically I'm going to get MCP600 pump... it says 1/2" barbs does that mean ID or OD? The heatercore I plan on getting has 1/2" OD barbs which I'm guessing equates to a 3/8" ID? it's the black dual heatercore from voyeurmods.com.Anyne know if the fittings on there are chaneable? I read on here that the flow will only be as good as the smallest diameter so does this mean everything else should be 3/8" ID too? Is 1/2" ID a whole lot better than 3/8" ID? Sorry for all these dumb questions but before I take the plunge i'd like to get all my questions out of the way. Thanks for the help guys!