Given that he's not a "flashaholic", and you're looking for a light to go with his car, I think you ought to give him two lights--one that can either serve as an EDC or stashed away neatly inside the car somewhere, and another easily accessible in the car at all times.
The Porsche cigarette lighter has good utility and looks very nice--it's definitely not going to be a blinding bright white light, but it'll be bright enough as a task light, such as looking at papers or finding something that has fallen inside the cabin. And it'll be easily accessible, resting in the cigarette lighter socket. So get him that.
In addition, get a nice P2D Q5 in black. It's a clicky switch light that takes 1 CR123 battery. The CR123 lasts a VERY long time. The P2D is powerful enough to be very useful, but small enough to fit most anywhere in the car. The P3D would be a good choice too, although it is larger.
Total cash outlay will be around $100 (if you buy the $33.60 Porsche light and get the P2D using the CPF8 discount code).
Anyway, that's my suggestion. Both lights together would serve him well.