For the wires: If you're going to be running off of deck power, the stock wires will be fine. I do highly recommend an external amplifier, in which case, I'd also run better wire.
For the amp: To match with deck power, it's unlikely that you'll need more than 100W (real watts, not max) for the subs for any reasonable sound balance. A class D amp will do this with minimal current draw, and be more than enough for a good sound balance.
If you're running an aftermarket deck, it will probably have outputs for the subwoofer. If you aren't, or are running a cheap deck that doesn't, most amps will also accept "high level" inputs. In that case, you simply tee off of the speaker lines, and into the amplifier. Most 2 channel amps will also have a low pass filter, which you can then use to be sure that you get only bass frequencies to the subs.
The choices for wiring is all up to your choice of deck and amp.