Unless you’re going to take the time to mask the silver coat in select areas to simulate scraping when it’s removed after the black coat silver would be a waste of time.
It all depends on what kind of look you’re going for. I wanted a weathered look for my pack, so I did a coat of primer followed by a coat of silver, then a coat of satin black. I only let the black dry for about an hour and then I rubbed all of the high spots with a piece of steel wool. The paint scraped off quite nicely. If you’re going for a “new” look however, the silver isn’t necessary.
As far as speakers go, it just depends on where you have the room. I put one behind my cyclotron and one next to my powercell.
On my pack, I only cut one hole, for the speaker that sits behind my cyclotron. The speaker faces my back, and is actually pretty loud. I used two three-way car speakers in my pack.
The second speaker, which sits next to my powercell, I just mounted on some standoffs, still facing the motherboard, but with no hole. I like this setup because it gives the sound some dimension, and it sounds like the pack is actually doing something inside. You can see the screws in this picture where the speaker is mounted.
fitted the various parts to the motherboard and fitted the ribbon cable from the cyclotron to the ribbon hole and it is looking sweet mate. I started on the ageing. I am using steel wool to slowly work off the black paint exposing the silver paint underneath.