I have a set of the bare version at a shop now. Going to see what it actually costs me once they are done. I bought them from Jeg's when they had a sale going on just to try them. The castings look good and reputation of the EQ heads is pretty good, from what I have read.
Whether you get bare version or the assembled version, have a high quality machine shop check the valve job and valve guide clearance. Also realize these are cast as stock Magnum replacements, so if you plan on big lift numbers you may have to have the guides shortened a little at the top. Factor these costs in, then compare it to what IMM sells them for ready go, already checked, corrected, and set up for your cam specs.
The listing on Jegs site says max valve lift is .510". Not sure if there is a little more room there or not, but most stock Magnums can get away with a little more than that if it's not too aggressive in valve timing events.