OP, have you test ridden Di2? I took a Domane out for a 30-40 minute test ride with Ultegra Di2 and thought it was cool but wasn't exactly blown away by electronic shifting. I still may do that as my next upgrade but I'm going to give it a lot of thought before I spend $1500 to go electronic.

I got a Powertap G3 wheelset for Christmas and love riding/training with power. The Quarq is what $1500-2000? I don't know if I'd spend that much with cheaper options like Powertap, Power2Max and Stages out there.