I believe the stock box mounting tabs are in the same plane but at different heights. Do the Borgeson tabs match the plane and depth of the stock tabs?

Looking at your angle, I can see where that offset multiplied at the end of the pitman/idler could require an offset of 9/16 on the tie rod

Shimming is not a bad situation and can even be required in stock box mounts to get the center link position set properly. Shims are occasionally required with spring hangers to adjust thrust, and some car makes require them for setting alignment. I'd shim before I'd start cutting or bending anything.