I'd say "Cool, screw the job let's go for a drive!!!"
I asked this about 7 months ago, and BTW I didn't drive the car. Some of my clients know about the car, but overtime we have become friends and thus shared stories about our interests. I have a hard time hiding mine when people are genuinely interested and I feel that they already have respect for what I offer. These clients are more than happy for me and tell me that I deserve it. OTOH I've had clients ask me if they paid for my pick-up, they definitely will never see the car. I can forego a cool drive once in a while (did I just say that) .
I know of a CE (computer engineer) that worked for IBM in Sweden in the late 70's who used to drive an old Rolls Royce. Since this was his daily driver during the spring/summer he also drove it to the customers. Some of the customers he was visiting complained "no wonder you charge us so much when your technicians are driving Rolls Royce's" so he wasn't allowed to use that car while working after that. /Peter