If you want no wires (ie. BlueTooth) go for something like a latest generation Scala. Just take a bit of care that you daisy chain the items together in the correct sequence. Most of the 'Help... It don't work' pleas seen on this site are down to bods simply lumping devices together, rather than following the correct sequence. Reading the manual(s) helps, too.
For hard wired, Autocom (which will take BlueTooth, too) is reliably popular. Again, there are very good diagrams available on how best to join items together. Use them.
Loads of threads, websites and other sources available on how to power all the gubbins.
One tip:
Work out how often you REALLY need to answer a phone or make a call when riding. Your thread would seem to indicate you have never used a phone on a bike before.... Somehow you have survived... The chances are you'll survive forever without the ability. Same thing with bike-to-bike communications... Do you have anyone to talk to? Do you really have anything so important to say to them (and them to you) whilst hooning your awesome steeds down the twisties, that it can't wait?
Another tip:
Do you REALLY need spoken instructions from your GPS device? The advantage of using the device as a simple scrolling silent map is that it forces you to THINK whilst riding. More often than not by using your eyes (and a degree of common sense) many of the errors bods report can be overcome by employing a little common sense when riding, rather than entering a dream like state whilst some computer generated bimbo whispers in their ear.