Looking for 72 or close ring and pinion, need 3:36 or close, would like new if possible.

Thank you

US-spec 107's (in the early years) came with a 3.07:1 rear end. Is the one you're looking for from a non-US car?

This guy would be a good source for a new one (he doesn't sell used parts) if they are available:
MBZ.ORG official parts vendor: Rusty, see http://parts.mbz.org