PBR do have a full upper plastic set, and like mentioned by goodolddays above, I have some old ones from mine so if no luck with goodolddays sign out and I'll check mine.

Ok, thanks.

This is interesting, I emailed Ni-Wumpf about the ground mods and got the following reply:

No Anthony – we do not recommend the ground modifications.  We do recommend that the wiring harness between the CPU and the driver board be critically examined for bent/broken/weak pins, and those pins replaced.  There is also a mod. to increase the +5 / GND connections between the two boards, and that is a good one to do.  Lastly, John’s recommendations on the power supply are good, but a better route to take would be to take apart the power supply and re-flow all of the connector pins on the solder side if they need it.

I think the +5 / GND connection mod he is referring to is covered here at 4.2.1:

http://www.pinwiki.com/wiki/index.php?title=Gottlieb_System_80#System_80B