Chem geld is more for normal humans. Marines go through decades of surgery, hypno-training and indoctrination. From what I can see, and what I know of the 40k universe, anything that doesn't make them a better warrior is just done away with, one way or another.<br/><br/>There's nothing wrong with having a techmarine, it's just that other aspect doesn't really fit with everything else.<br/><br/>If we were playing Black Crusade, I wouldn't bat an eyelid at it, but I just don't feel it fits Deathwatch.