I just received my new V1 for my 2 week old 07GS350... I am trying to do the same thing. I have done the wire splice for my other V1 on my other vehicle without a problem.
Here is what I have tried so far but not having luck finding a wire with power...
PIC 1 (general picture) - Have tried tapping into Mirror (pic 2), sunroof (pic 4), main wire grouping (pic 5)
Results below...
PIC 2 (mirror) - tried light orange, dark orange, & red wire. No luck only two left. Will try those today.
PIC 3 - have not tried, will leave to last if all else fails
PIC 4 (sunroof) - tried the gray, did not work. But then thinking about it. most likely none of these would work since the sunroof is activated using the console buttons.
PIC 5 (main) - tried gray but no luck.
PIC 6 - I Have not tried. i am assuming that this is a compass or external temperture monitor
PIC 7 - Have not and will not try since this is the phone mic.
Please add acomments of what you have found out. I will try the remaining two wire in pic 2. Since mirror turns automatically when the car is started.