do the Vehicle Inspection Computer need to connect to any other computers?
do you have Static IPs from your ISP?
if you have mor then one Static IP, you could use a switch and connect the Netgear and the SonicWall to it.
if you have a dynamic connection, change the WAN IP of the SonicWall to 192.168.2.254 and enter this IP into DMZ zone of the Netgear. If Activant needs access to a certain port on the SonicWall to access the Data, you will need a port-forward in the Netgear.