No it is not Di2 ready but it is quite easy to make a neat job.
I have drilled a hole for the grommet in the down tube then routed the wire inside to the BB. The internal battery sits inside the seatpost and the wire from that also drops down to the BB area. The only part i did not route internally was for the rear mech. For this I drilled a hole in the bottom of the BB shell and took the wire directly out through another grommet and used the shimano cable cover to run the cable on the under-side of the chainstay.
Then for your wires around the BB, I find it is best to use superglue to bond them around the outside of the inner BB shell to keep them away from the BB spindle. I mounted the internal junction box right at the bottom of the down tube near the BB shell.
For me it was quite an easy install although of course make great care with drilling the holes. I own a company that manufactures the wiring harnesses for F1 teams such as Mercedes, RBR, Lotus etc so wiring is second nature!!
That's a good tip with the superglue, I was going to use tape.