Sirius
It's not that difficult.
The first thing to do, is determine how old your Sirius unit is. If you have a power wire that goes straight to from the unit to a standard looking cigarette plug, it's pretty straightforward. This is how the older models are (i.e. 3 years or older). You can pop open the plug, determine which is the positive wire and which is the ground (hint: the wire connected to the fuse is the positive wire, the other is the ground), and connect it to the power source.
If you have a newer Sirius unit (three years or newer), there's a twist. You can tell if you have the newer unit, because the cigarette lighter plug will have the dog on it. The plug itself is chunkier, and a portion of the plug is formed into a circle with the dog. At any rate, you need to open this up. There is cicuitry inside. You need to be careful to leave this intact. I believe it's a resistor that takes the 12v feed and reduces it to 5v.
Again, determine which is positive and which is negative. I then solder a wire onto the positive and another to the negative. I then run these wires through the plug. I don't have a photo, but if you can imagine leaving the plug wiring intact, and simply extending the positive and negative wires so they are longer, and keep the resistor in place, you're on the right track.
From there, I take these wires and run the negative to the ground, and the positive to the positive source. I found both under the dash. The ground is easy, just look for a solid chassis bolt. For the power lead, get a good multi-meter and look for a 12v power source.
At this point, you need to determine your preference. I like a constant 12v power to my Sirius unit. This allows me to turn the key off, and still maintain power to the Sirius unit. My unit has memory, so I can leave my car, and have my program still record. It's there for me when I return. I can also build a buffer of programming, so that when I enter my car in the morning, I have commercial free content. The downside, is if your battery is weak, you can run the risk of a dead battery. But in 5 years, this really hasn't been an issue for me.
The other option is to connect to an ignition-on power source. Use your multimeter. If the 12v power is gone when the ignition is off...that's the one you want.
At any rate, tap into the fuse/circuit that meets your desired scenario. Attach the ground, cleanly route the wiring, and you're good to go.
One thing I've found with my 4Runner, is that by tapping in at the fusebox, I pick up quite a bit of ignition noise. The power signal is dirty. I've found the same with my cigarette outlet as well. So taking the juice straight from the battery is probably the best option. I just haven't yet felt compelled to do so.
I hope this helps!
