Plug welded from the sides, Cut out the upper & lower & welded the seams. Then cut out the inner sides where the cross member welds in to the rails tying the pieces together. As far as the lower mounts there are only a few locations that they can go, If you use the Mustang rack you have to run @ 60.5" track width ( That's why A.M., Scott & XV use the same width.) It has to do with where the inner tie rods line up with the upper & lower arm pivots to control bump steer. I'll address the outers when I get to them & probably have Scott make a set for me..In hindsight I should have bought a weld in stub, But then I would have never learned what I have about what it takes to make a front suspension work...