Pick a RAM distributor? I would send an email to Crucial and G. Skill and ask tech support what DIMMs were available with the fastest Micron D9's they had available. Then I'd probably toss that idea around and go with Crucial value RAM or some crazy discount priced high rated G. Skill gaming kit. Kingston value RAM is good if budget is a concern.
Some of the Micron D9 kits various RAM distributors have available. Micron is the parent company of Crucial. Crucial is Micron's RAM distribution name.