Uh, I have just noticed that I have not updated this post for years!

I don't want you to think that those two games have been trashed: they are fully working now!
In particular, I had the opportunity to work on them starting from this summer.

WGP was the first of the line because it was 90% working and not too much work was predicted. After a good cleaning i replaced the (linear) not working secondary PSU with a switching PSU. As it was juicing the rumble motor, this (and reconnecting the cables) was all it needed to have it back to work. Another problem was the audio: only one channel was working. After some google i noticed that TAITO's are known for audio problem caused by the op-amp going bad. Piggybacked the old IC and the channel started working right after... yes! Last problem was mechanical :the springs that keep the wheel in place where broken, so i had to replace them.

Race Drivin' was another story: i knew it had some board problem, mechanical and the monitor had color issues. This board is incredible: it gives you the position of defective RAMs and you can bet that replacing them the pcb will work! I had 2 defective VRAMs and by replacing them the PCB was fixed! I would never be able to fix it without those self test, great work ATARI! While doing this, the monitor died. It had xray shutdown, but trying to fix it i shorted the EAT (and i am not a noob on this ). Being a zenith K7000 (K7000a) i had to replace it. Found that MTC9110 is a good replacement for those (you need to swap the neckboard socket and place a higher value resistor in series with the filament, 2.2 ohm if i remember well, i wrote this somewhere else so if someone need the correct value i can source it and replace some connector) and it really is
Some additional work (greasing of the pedals, cleaning of the cab, a good revision of the "new" monitor) and now it works great!

I have some pic on the phone, let me see if i can upload them...

Gorf is still available.