As it stands right now, the Technicals seem relatively plain. Given that the conflicts that inspired Sandstorm have some truly impressive modifications of varying degrees, I think it would be an excellent touch to give Security and Insurgents each their own touches.
The interiors of the Technicals are practically bare. These are the vehicles transporting people into combat? It could be really nice to have some small details that make them feel more personalized. For the insurgents you could have seat covers, a necklace hanging from the rear view mirror. Small touches that put you in the moment more. Sandstorm has always been an immersive game, that should extend to tactics involving its vehicles.
Additionally, each team's technical could be made more recognizable with a few distinguishing features. Have some haphazardly welded armor plating for the insurgent technicals -- examples of this in the real world are endless. It would also make the car itself being able to soak tons of bullets to the body feel more logical from a player's perspective. The security technicals could have a grill on the front meant for ramming or moving vehicles, and maybe some kind of camouflage on it that's in keeping with the rest of their uniforms. If not camouflage though, the amount of dust those things accumulate in a desert war zone would certainly be noticeable.
Any other ideas would be more than welcome.