I’ll second that this is pretty easy and can be done very cleanly. I was just running another wire from the handlebars earlier this week.

Run the wire from the GPS mount down the handlebar, through the cable holder/cover (under the handlebar) along with the other wires. In the opening where the handlebar moves when you turn, feed the wire through the opening towards the area under the left cubby (cubby should have already been removed to give access). It should come through just below the left air intake. If you wire is too flexible, push a stiffer wire underneath the left air intake towards the handlebar opening. Once it comes out in the opening, tape your wire cable to the stiffer wire and then pull the stiffer wire and your cable into the below-cubby area.

Use several cable ties in several places to hold your power cable to other wiring coming down the handlebar. At the bottom of the handlebar leave slack for the movement of the bars so that the cable has slack and does not bind or get pinched when bars turned fully left or right.

Make your power connection to the switched 12v connector under the cubby. If you want your GPS audio to input to AUX, you can run that cable the same way.

Reinstall cubby and wa-la, a nice clean installation that is almost totally invisible. And, no grommets required!

I used this procedure fir running my GPS power and audio cables, and also a PTT cable.

Hope this helps.