Weight wise - there comes a point were it just don't matter. I just checked the flier for the local CX season opener and the "A" (longest) race is 60 minutes. At a race like that your rig could go plus or minus a few pounds and it will not figure into your final result... unless you're some top level dude... and if that's the case you'd already know that it's training that gets you the results.
Top gear is cool, and more power to you if you can swing it $, but it's training, not gear, that gets you the results.