Recently I picked up one of the spiral wireforms mods for Twilight Zone. I heard a couple hundred of these mods were originally made, and they seem to sought after on the used market. Recent eBay sales have realized $320 on up. I don't know who originally made them, and any leads I chased did not product any results (no returned emails).
To the point... I finally got around to installing it and promptly ran into an issue.
As the end of the wireform it had place to install a rubber bumper pad, though no pad was present. I have not seen these mods ever offered with a pad, so I assumed that the installation would require you to remove the round blue rubber pad from the stock TZ wireform and refit it to the spiral wireform mod, which I did.
Unfortunately I quickly noticed that the pinball would often bounce out of the return lane after traversing the wireform and making contact with the rubber pad.
Solution: I grabbed a thinner blue rubber pad (23-6702) and installed it in place of the thicker rubber pad (pn: 23-6686).
Now I thoroughly enjoy the mod. IMO it adds a neat element to gameplay and doesn't obstruct the playfield (which was the concern of some friends). I'm glad to have worked out the issue I had with it., and wanted to share my solution with the group.
Note: Also, my opinion, the only other drawback is that I don't think you can fit the spiral wireform AND that cool slot machine mod at the same time. I don't have the slot machine mod, but I don't see the two mods working together due to the wireform's design. If anyone has anything to add on this topic, please do.
Stock wireform rubber pad pn: 23-6686
Thinner rubber pad pn: 23-6702
Note: this thinner pad is used in the tough up-kick on games such as Judge Dredd. As of Jan-2014, Marco didn't have them in stock, but PPS seems to.