Under-Dash Auxiliary Power

[hgray14]

(sorry if this is the wrong forum but I already posted to the Audio/Visual forum in "Modifications" and only got one response.)

I have a 1995 Volvo 850 Turbo and am looking to power three things via hard wires, instead of using the cig lighter. The three things I want to power are 1) my aftermarket Tire Pressure Monitoring System, 2) my smartphone dock, and 3) the OBD 2 (I don't want the OBD 2 to have full-time power (like it currently does) because I don't want it powering the bluetooth transmitter when the key is out of the ignition.)

So...I found the yellow plug under the dash near the steering column that has auxiliary power but now have a couple of questions. (I am referring to 24/35 on page 118 of the wiring diagram, which states:

A:1 30+ supply

A:2 +X supply

A:3 Main beam

A:6 Rheostat variable supply

A:8 Gound connection

1) What are the electrical wire ends called that fit into the yellow plug? I don't have any and need to buy some if I am going to use this outlet.

2) The +X supply seems to be the only one that is useful for what I am doing - how much power is running through it? Is it 30 Amp?

3) Would I be better off just splicing into the wires leading into the cigarette lighter? It certainly would be easier what with all three wires already having been routed to that point anyway.

4) If the cigarette lighter isn't enough power, how about the stereo?

Thanks for any advice you can give me