My personal advice on the Willem would be to see how far you can throw it. Hateful things, those. I know some people love them, but I was very much not impressed. Most of the problems revolve around the abysmal software and the lack of good program voltage power supply.
But, at least on Pole Position, it shouldn't be that bad, it takes mostly 2764's, which even the Willem can handle (usually).
You'll need an EPROM eraser, EPROMs are erased by UV light of a specific wavelength. If you don't have one, building one is pretty simple - I made my own using a UV tube I got at the pet store, it's used in pond filters to kill bacteria.
Also, in Pole Position, those ROM errors aren't actually problems with the ROM chips. They're problems with the board, the power distribution, and the sockets.
-Ian