I'm running a ysi with a cog drive on a street car with an M6. No issues at all with the drive other than something got between the crank cog and the belt and caused the belt to come apart in the middle and gouged the cog. I dremeled down the sharp spots and luckily had an extra belt on hand. No problems since.
I made 825rwhp/639tq with it on 93 octane. Since that dyno run, I installed meth as just a safety feature, a cam speced for the engine, and pullied down the blower. I went from 15.xx lbs of boost to right at 20# of boost. I don't know what it makes now but it is noticably more powerful. I am guessing around 900rwhp but will dyno it soon.
I am running a procharger 77T crank cog with a 27T blower pulley. Before, I was running a 75T crank and 32T blower pulley. I also paired it with the BV57 blowoff valve too. There is nothing stealth about my setup.
If you have any other questions, PM me as I often forget to check threads I have posted in.
Oh, the cog setup sounds badass too...