Your subs do not come wired a certain way. They come with certain voice coil configurations, which allow them to be wired in different ways. Ohms is the impedance, or the resistance, of the voice coils. Each of your subs has 2 voice coils. Each voice coil has a nominal impedance of 2 ohms. So you have 4 voice coils total.
Each sub can be wired to it has a total nominal impedance of 1 ohm or 4 ohms. This is accomplished by either wiring the 2 voice coils in parallel or series, respectively. Now you have 2 subwoofers, both either at 1 ohm or 4 ohms.
Now you take these two subwoofers and hook them up together either in parallel or series.
If they are each wired to 1 ohm:
-wiring them in parallel will give you .5 ohms total nominal impedance
-wiring them in series will give you 2 ohms total nominal impedance
If they are each wired to 4 ohms:
-wiring them in parallel will give you 2 ohms total nominal impedance
-wiring them in series will give you 8 ohms nominal impedance
With your subs, there is no possible way to use all the voice coils and get a 4 ohm load.
Each sub can handle 400 watts. So you want about 500 watts for each, for headroom. So you will be looking for about 1000 watts at either .5 ohms, 2 ohms, or 8 ohms. 2 ohms will be the most common in mainstream amplifiers, so look for that.
As for actually wiring them:
The 4 gauge wire is your power wire. This goes from your + battery terminal to a fuse within 6-18 inches from the battery, then to your amp. Then a short 4 gauge ground wire will go from the ground terminal on the amp to a solid metal ground point on the vehicle. Sand it down to bare metal before attaching the wire to it.
The RCA cables go from your HU to the amp. They send the signal only, very low level.
Now you need speaker wire to go from the amp to the subwoofer. 12 or 14 gauge will work fine. Also use this between the terminals on the subs to wire them up.
Don't forget a remote lead from the HU to the amp so it will actually turn on. Some RCAs have these built in, you just need to connect them to the proper places still.
If you have any more specific questions, just ask
