Probably like most of you reading this, you have a suspected optispark problem, and have read that there are no good optisparks, including from recognized high performance brands, and that the best optispark to get is one from Delco with a Mitsubishi sensor. You may have also read that these were discontinued, as I did, so when I saw this available, I quickly ordered it, but I was quickly disappointed. I knew it was rebuilt, so I didn't expect cosmetic perfection, but there was a scraping sound when spinning the shaft, so I had to investigate. I disassembled the distributor and found several unwanted surprises. The scraping sound was from a bent optical wheel, which would scrape the optical sensor, which seemingly is the most important part to protect. I also noticed different size screws, where one had been stripped and replaced with a larger size. That's not ideal, but I know that is considered acceptable in a rebuilt part. What isn't acceptable is finding pieces of plastic inside from where the edge of the distributor cap cracked off, perhaps from rough installation. There were also metal filings that were not cleaned after machining or sanding or whatever process left them. The shaft was secured with a weld, instead of a pressed pin like on a new distributor. It can be debated if the weld is better than the pin, but it looked more like a way to compensate for a worn or damaged part, instead of to improve reliability. Even with all of these problems, at least inside was found the prized Mitsubishi sensor, purportedly the only optispark sensor that can be relied upon.After cleaning up the distributor, straightening, and reassembling, I went to install it, but found the connector was different than the one on my old distributor, and would not plug in without a minor modification. After removing the old distributor, which I suspect is a low cost no name brand, I did notice that the Delco distributor had less play in the shaft, though whether the slight play in the old part was due to being lower quality or slightly worn, I do not know. After all of that, at least the new part worked. I couldn't tell any difference in how the car ran, but it did run. I now expected to have a distributor that I could rely on for several years, but the next day, the car wouldn't start. I tried several things besides the distributor, because it couldn't be that, but as it turns out, it was. I finally disconnected the revered Delco distributor with the Mitsubishi sensor, connected the old one, spun it by hand, and was able to get spark and fuel that I couldn't with the Delco part. I sent the distributor back for a replacement, another Delco. This one looked better overall, no cracked parts, no bent wheel, no mismatched screws, and a pressed pin instead of a weld, but NO MITSUBISHI SENSOR! If you buy Delco to get the Mitsubishi sensor, you are taking your chances, since I have learned first hand that not all of them have it. After having one fail, I no longer considered it important to have the Mitsubishi part, so I installed the replacement Delco with the mystery sensor. The car continues to run fine after several months. Next time I need an optispark, I may try a cheapie, since I don't know if there was any benefit to getting the name brand part.I now question if I needed a distributor at all. The car was running rough and giving an optispark code. A distributor change didn't help, though cleaning two clogged fuel injectors did. The car had been worked on quite a bit by the previous owner, who may have really needed a distributor and changed it, but never got the car running right, and may have had old codes on it still. After clearing them, the codes didn't come back with the new or old distributor.