I guess I don't see where 5/16" wall tubing is any sort of advantage, the crossmember is only as strong as the frame it's attached to and I don't see why anything this side of a semi would need a frame or crossmember that thick! Ya , the old stuff with the stamped steel arms and the strut rod aren't that great, but the op already made it clear he has the tubular a-arms that don't require a strut rod.... My thing has always been that the construction technique and detail is far more important then the mass and bulk of the material used!!! All of the crossmembers should have extra gussets to the lower a-arm attachment point, IMO one is not enough, but again, no reason to make that gusset any thicker then the structure it's welded to. I was around when Fatman was new, and their fitment and geometry was questionable at best. I'm sure they've improved over the years, but IMO they aren't the best unit on the market but do offer an acceptable product at a decent price....

Unfortunately, many of these IFS kits have been installed by folks less then qualified to do it, and many are lacking in the knowledge of basic fabrication techniques, but that's what the market wants so that's what the market gets!!!! I much prefer building with round tube, and seldom (if ever) use anything thicker then .083" wall and have never had any trouble. But a "first timer" using lightweight material would have fits trying to make it structurally sound! My point is, all of the MII suspension package manufacturers are playing in a very competitive market (price wise) and many have resorted to questionable materials (larger, thicker, bigger, etc.) as a selling point! But, then they also have to try to make their components "idiot proof" for the at home d-i-y guy who may or may not have the necessary expertise to do the build/install correctly..... As with many things involved in a build, there is seldom a clear cut winner in the "this is the best" product wars, and it comes down to preference and past experiences with a supplier......