That's odd, I was under the impression that the S-R bumper could also mount with the OEM frame stiffeners?

You'd think the mount points would match up?

The Shrock one's I used were thicker than the OEM's, but the holes were pretty much in the same places on the frame and so forth...

Is it possible your frame has been tweaked a bit?

If you bolt one end, and try to shim the other until it matches, would that be it...or is it that you need to MAKE holes in the stiffener or frame where you need them?