I am looking at purchasing a Cervelo R5. My local shop has one frame in my size. The problem is that they don't have the groupset to build the bike other than a Shimano Dura Ace 9170 Di2. Ideally, I would get the Shimano Ultegra Di2 12 spd or SRAM Force 12spd which are what Cervelo has as options as I would not want to spend the extra for the Dura Ace. But since they don't have either of those, they are offering to assemble with the Shimano Dura Ace 9170 Di2 11spd. They will charge me $1000 more than the Ultegra Di2 12 speed. Should I take this or wait for them to get one of the 12 spd groupsets?