I own one. I know it is a "1" shot game, it technically isn't but there is one shot to make big points, the ramp. I LOVE cars, racing and Porsche's. That is why I finally got one.
The pf with age, probably has those hair line cracks in it.
The ramp will be cracked or missing where the ball ejects out of the scoop in the rear left.
Fading on the cab, pf and backglass of the red/pink color.
Check for battery acid leaking, mine has it, fixed but looks horrid.
The speed sensor is really just 2 switches on different places on the ramp.
Now days, if everything is in good shape you could go 800-1000, if things are broke etc lower, but a minty one...mmm that could go 1200+ I would assume. The last couple that sold around these parts were like 800 isssshhh I think.