The main reinforcement prototype is pictured below. This was used for layout and testing purposes. The production version will be better looking, but the layout will be identical. Paint will also be MUCH better on the production parts. The large solid square stock strip running top to bottom helps limit vertical expansion (the type most likely to accompany added gear clearance) and the cross-bracing strengthens the assembly against torsional flex spreading back from the area around the front pinion bearing.
Something to note. Because prototype layout is much easier and quicker to do using a messy MIG machine, the welds are a bit bulky. For aesthetic purposes, the production version will use much nicer TIG welds, pictured below... For the sharp folks: you'll notice that this is the weld in the bottom left corner of the prototype.
The base plate is cut out and then I clamp it into a jig on my milling machine and end-mill the cut sections of the plate to ensure a nice finish and very straight machined cuts.
As for the bolts, here are the class 10.9 bolts in a black oxide finish next to the stock class 8.8 bolts with the light metallic zinc finish.