You cheapskate - of course you should. At minimum, invest in a mesh rear wind screen like the one we profiled above to reduce backdraft but retain a decent amount of airflow. These units generally go mounted on the roll bar for easy installation and removal. Solid rear windshield are also useful, though this author strongly recommends one featuring a vent of some sort in order to keep air flowing and exhaust the dust that will inevitably enter the cab. The rear windshields with a sliding window - like a pickup truck - are pretty neat and add a lot of value to your rig.