I agree, if it's a working original, don't mame it.
If it's a poor conversion ... well, people will love to buy the working wheels, buttons & pedals, and even the control panel. [shrug]
If it's an original, you could buy it and reproduce it, using the reproduction as the mame cab. Then fix up the original and sell it.
2 player or 3 player?
Championship sprint is the two player version. It
could be a conversion, but even working conversions can go for $300 and up.
(Super Sprint is the 3 player)