I have a g540 and I am about to buy steppers. I am up in the air about these two. Which should I get based on specs?

These http://www.kelinginc.net/KL23H284-35-4B.pdf

or these http://cncrouterparts.com/specs/NEMA23_Specs.pdf


Also would this power supply be ok for the g540? Its the S-350-48 model.

http://cncrouterparts.com/specs/ModelS-350W.JPG

Thanks