A Tulsa belly pan is a common addition to protect the oil filter, coolant reservoir, and other lower engine parts from road debris. I purchased one from HDL.
The Tulsa belly pan is just a sheet of metal. If you have simple metal fabricating tools you could easily make your own.
Installation is easy. Loosen the two 10mm nuts on both sides (arrows). Slip the belly pan up underneath the exhaust covers. Slip the front piece of the belly pan in place and attach it to the rear piece with the quarter-turn fasteners. The fasteners are a little bit of a pain to attach properly.
You can see the now protected oil filter. The normally exposed coolant reservoir is now safe, too.