Pilot other stats and vehicles, How is this handled? Options

[SunJester]

I am trying to work up a modification for the smuggler in the SR4 rule book for one of my players and I am trying my best to understand how pilot and other stats are upgraded on a vehicle.

The smuggler has a GMC Bulldog Step Van. The unmodified pilot for this van is 2. The version that the smuggler has has Pilot 4, Firewall 4, Signal 4 and Response 4.

On p. 214 of the rulebook, you can find:

Pilot is used in place of System for vehicles, drones, and agents, but otherwise has the same function as System.

In the Rigging and Drones section on p. 238 the book indicates that riggers will have

plenty of drones with amped Pilot, Response, and Firewall attributes of their own

These quotes seem to indicate that Reponse, Firewall, and Signal are upgraded independently of Pilot. In other words, upgrading Pilot does not automatically upgrade all of these other attributes. Is that how I am supposed to be reading the rules? Do I use the hardware upgrade costs on p. 240 to upgrade Response and Signal on the van and use the Program Costs and Availability table on p. 228 for upgrading Firewall on the van?