Interesting conversation. Thought I would wait a while and see what came along before offering my comments. No worries! We have sold over 30 of these gearsets without a known failure. So, let me address some of the concerns submitted.
The syncro teeth on the gear mesh with the sliding syncro sleeve. This unit is pressed onto a splined hub in the standard Alfa gears. Conversely, the OSG syncro tooth unit is welded onto the gears and as Richard points out, can be removed and a new one welded in place if necessary.
The stock 5th needle bearing is much smaller and is a comfortable fit in the 5th gear with room to spare. The 1st-3rd journals are much larger and require a much larger bearing. The stock copper bushing is very thin and allows room for splined mounting of the syncro unit.
Why do the OSG syncros need to be welded instead of splined? This is a neat piece of engineering. I have always made my own gears, hated the copper bushings that go bad and tried my best to fit 1st-3rd with needle roller bearings. The limiting factor was that the copper bushing is very thin and the needle bearing is much thicker. There was simply not enough meat to bore out the hole to fit the needle bearings. One has to machine off most of the metal base supporting the mounting splines to accomplish this. I even selected the same needle roller assembly that OSG ultimately used, but could not make it work. Mr. OS ingeniously attached his syncro unit by welding which leaves sufficient meat to bore out the cylinder to fit the needle bearing.
Bill has done a very thorough job documenting the metallurgy. So, I see no stones left unturned with regard to the quality or functionality of the OSG gear sets we have been selling for several years.
The only thing that has not been mentioned is that performance can be enhanced by REM finishing the gear sets before assembly. This is a process that tumbles the gears in a matrix of special stones and a chemical bath of polymer solution. This micro polishes the tooth surface and works the polymers into the pores of the metal. For friction reduction and longevity, this process is superior to any coating. This makes the gears so pretty that it is a shame to hide them inside a gearbox.
We have REM finished several sets for customers since Bill made his purchase and have now decided to offer it as an option on our website. This also works wonders for ring/pinion sets. Every little bit of friction reduction from engine to differential adds up to significant reduction of parasitic power loss.
Unfortunately the current prices will increase with the next run of OSG gearsets delivered. We currently have (probably) the last of both the close and super close gearsets on the planet until the next batch is done, so grab one now if you have been inhibited by the misinformation. ( Please note that some pricing on our ABB ads need correction, but they do not perform that service that anymore. So it will have to wait for us to generate new ads. )