Ive installed two kenwood subwoofers and a Vibe Slick A7 monoblock into the boot of my car. I presume you are putting the subs in the boot. I have upgraded the head unit to an rns-510/mfd3 though. Basically there is a connector that supplies the power at the back, you need to strip back the wire connect a remote on/off switch (because you do not want your subs draining your battery). The power cable is running down the passenger side and the rest are running through the center console under the carpet back under the back seat and out into the boot.
This is my spec:
Sub spec per sub:
Peak Power - 1200W
Maximum Power - 800W
Rated Power - 400W
Frequency Response - 25Hz - 800Hz
Sensitivity - 90 db
Impedance - 4 ohms
Vibe amp spec:
Type : Mono Bass Amp
Height : 2.5″ (65mm)
Width : 16.7″ (425mm)
Depth : 9.7″ (245mm)
RMS @ 4 ohm mono : 1 x 300 w
RMS @ 2 ohm mono : 1 x 600 w
RMS @ 1 ohm mono : 1 x 750 w
Max Power watts : 1300 watts
Freq response : 10 Hz - 500 khz
SNR : 85dB
Crossover type : LP / Subsonic
Crossover range : 35 Hz - 250 Hz
Now if your running this amount of voltage you will probably have to do the same as me and upgrade the alternator, you may not need to if you have a gti/tdi. Standard 1.4 is 110 amp you'd preferably need 140amps.