What wire to use instead of Romex

@jea48 

Questions:

How much of the the exposed MC cable will be seen in the garage before it enters the wall of dwelling unit?

The living room wall where the outlet will be is directly above the garage door. The cable will run from the ceiling of the garage down a foot or so, then to the left over the pedestrian door, along the wall with the panels, and down to the lower of my two panels (wired together to function as a single panel rather than a main and a sub). Or, it could run across the ceiling, then down to my panel. That'd be a shorter run.

What is the garage wall finish of the wall it will be installed on? Example, wood studs covered by drywall? Cement block? Other?

Wood studs with sheetrock/drywall, with plywood over it where the panels are.

Horizontal elevation off the floor of the MC cable? Distance down from the ceiling?

Is the electrical panel surfaced mounted to the wall? 

Vertical length of the MC cable above the electrical panel  before it is installed horizontally?

I haven't taken measurements, but you can probably ballpark them from the photos. And yes, surface mounted panel(s).

@roccity 

That angled flexible metal conduit feeding the small load centers is butt ugly... 

The HOA shouldn’t question your use of MC cable. Good thing about 10-2 solid copper wire MC cable, the solid #10awg copper wire stiffens the metal armor so it can look more presentable to the eye. 

@roccity 

It just occurred to me, your Condo electrical wiring is not fed from any of the load center panels in the photo you posted. Where is the electrical panel that feeds your Condo unit located? I assume somewhere in the Condo.

Why are you wanting to fed a dedicated circuit from one of the load centers in the garage? I’m not sure what the feeder ampacity rating is for the load center panel you are planning to use, or the existing loads on the panel.

More info is needed.

Like where is the panel that feeds your Condo unit in regards to where the new dedicated audio circuit wall outlet will be? 

@jea48 

My condo has a subpanel in the kitchen with individual breakers for the different circuits in my home. The two panels in the garage (the Square-D panels with one sitting above the other) are my main panel. If you look closely, you'll see a 100-amp tandem breaker in the top panel labeled "Condo." This feeds the subpanel in my kitchen.  The electric meters are on the exterior of the wall to which the panels are mounted.

My thinking is that the total load on my main panel remains the same as I won't be adding any usage but rather just redistributing it, and so exceeding any capacity limit is not an issue.

Let me know if this makes sense and clears things up for you.

Can't it be run inside the wall? Any competent electrician should be able to.