Its actually a 'conical' style syncro. There is a syncro inside of a syncro if you will. The only problem is the entire gear set/slider assembly is different if I remember correctly. There is the inner syncro piece that goes into the gear? (damm its been a while since i've looked at a dsm tranny) and then a syncro that goes over/around it. The advantages of it is the fact that there is more 'syncro' available to mesh the gears. Hince why the getrag's in the 3s's shift so nice when the proper fluid is in there, triple and double 'cone' syncros
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www.teamrip.com should have some info, also a quick search on dsmtuners or nabr should pop it up like jet said.