If I were trying to keep stuff out, I'd go velcro to get around the entire edge, rather than the body posts. This also lets you raise the EB48 body a bit by not cutting as high up as the line, to give more air space for electronics to breath in there and keep any air intakes you cut up higher to avoid more debris. You'll only need to cut small slits to go over the nerf mounts.

If you're only on dusty tracks instead of muddy tracks though, I've found that just the air guards and an air compressor after each run leave my truck pretty much looking new (except the bottom of the chassis) too. If you do a lot of dirt roosting with the wheels turned (drifting) to force the track into your truck though, then the guards will still help, but probably not as much as you're looking for.