I believe the IR3 can run on HP (I've run mine on it before I got the angel air) depends what year speed you have as they went LP around the the 05/06 ?
If you can get a good one (that works) they are worth having if a bit on the heavy side. They are just a reg so you would need to get hold of a bottle to screw it into.
check this link to some pics of my IR3 with the air angel setup.