At one time, I was a week behind on my child support because I'd spent about $2500 on the green Corrado (early VR6 timing chain tensioners, clutch, motor mounts, front stuts). She asked why I didn't sell the thing and buy something "new". I asked her how much her monthly payment & insurance bill was...seemed she'd spent about $7K on her car in a single year. I reminded her that even with the $2500 bucks, I'd only spent about $3500 on mine in the same period of time.
I'm with Type Q on this one. If the car's really the creampuff you think it is, any inspection (one or two hours labor, and only that much if they don't know you) by a good shop will show it. I've actually had professional mechanics say "..dude, you stole that car!" when I've been lucky enough to bring them a good one. Slip the technician an extra 20 bucks to document the good stuff on the shop's service order paperwork, and politely remind the girl's dad that he's no professional mechanic.