IMO Most 110V machines like Miller or Lincoln can do those welds, don't know about harbor freight or others, but probably most. I do prefer 220V. Any welding is dependent on skills. Mig welding can have plenty of penatration and is the easiest and more forgiving than the others. The skill level to do stick or tig is a lot higher. The right size wire affects penatration, a flux core can give better penatration, but the weld will be not as clean looking as solid wire that is gas shielded. These rear end housings are not that thick, I'm guessing where he's welding its 3/16" thick max if that. Steel structures being built nowadays are being welded with wire feed machines. On your brackets if you can, weld all around leaving no open joint because that's were a "tear" or failure can happen.
