[Tristan Lall]

Great work on the CAD; you've obviously put effort into realism and detail.

There are few minor details you might want to address:

1. A few components resting on the bottom plate don't seem to have adequate mounting tabs (the Victors do; the Spikes don't).
2. Add bigger radii whenever possible, to decrease stress concentration (there's a tradeoff to be made regarding weight). A few of the lightening holes are unnecessarily sharply cornered. (Also there are a couple vestigial lightening holes, e.g. in the near corner in the photo; get rid of them.)
3. Those bumper mounts are convenient, but very carefully scrutinize the 2012 rules, because your design would have been legal some years, and illegal in others. (Presuming that you recess the bumper backing into the frame rails, and depending on whether you add furring strips or rest it on the protruding bolt heads.)
4. The tall vertical chain-tensioning slots look like they may be a weak point, depending on how well you can clamp the frame rails together with the tensioners, and how much the chassis flexes overall. They interrupt the web, weakening it. Instead, consider a small vertical slot, only where you need it.