Performance for bmw v12 any ideas?

I have just recently bought a e32 v12 from a '89 750il which im going to put in my e36 325i. Im looking for performance parts for this motor (m70b50) but can not seem to find any parts anywhere. I want to bore it .30 over and try to make it a 6.o liter instead of a 5.0 liter with all forger internals and arp heade studs, also looking for a twin turbo kit for it from garrett turbos, any idea as to where i can find these thing? Also looking for a manual transmission. Does anyone one know where i can find a manual 6sp trans and what its from. I do believe that an 850i trans bolts right up but not 100% also if it does will it be able to hold up to 800 plus horse power or should i go to getrag and get one custom built?
Thanks Jesse