Looking good! A little advice: your gussets don't need to be as big as they are. It's not bad, but you could make them a bit smaller to use less material. Also, the extrusions on the sides that I take to be bumper mounts could be a little more solid. If they are indeed bumper mounts, it looks like a good collision would bend those mounts instantly.

Awesome job, though! Keep on submitting your models here and you'll get a lot of helpful criticism.

Edit: Also, while the pocketed aluminum bellypan is nice, it's not something you absolutely need. I find it's just there to look good, if anything. 6mm thick plywood has the strength you need with low weight as well, and is cheap and easily machinable. Plywood doesn't have the "cool factor" of a pocketed aluminum bellypan, but functionality-wise it does the same thing the same ways and is a lot more resource-friendly.