First time install

Visonik

Reciever VCD51

(2) 6 1/2 V62CS (200w max)

(1) 10in  VB110 (300w)

(1) 2 channel amp  V220S (2x75 RMS 2x150 max)

(1) 10 gauge amp kit

SONY

(2) 6x9's XS-V6921 (180w)

VR3

Xtreme 5 band eq VPE500S (seperate sub volume)

Use the head unit to power the 4 speakers.  Get speaker harnesses so you don't have to cut factory wiring.  Also get a receiver harness so you can just plug in to factory wiring behind the dash.  They should have both of these things at a place like best buy or circuit city, and Crutchfield also sells them.

You can use the EQ but usually you only need those when you have multiple amps that you want to control.  But if you want a dedicated subwoofer volume control it will work as that.  Just use the head unit's rear RCA outputs to connect to the EQ's input.  You said there's only one spot for the sub output?  Did you mean one pair of RCA connections? or just one single plug?  If it's just one single plug you should use the left/white RCA plug, and go to the amp's left channel.  Also set the amp to "mono/Lchannel" if it has a swich like that.   

You probably are gonna need to give the EQ a power, ground, and turn on connection.  To make things easier, just connect these wires to the wiring harness for the head unit.  While you're there, you'll also need to hook up the amplifier's turn on wire, and the amp's RCA cable.  Just plug the cable in to subwoofer output on the EQ as mentioned above, and refer to the labeling on the wiring harness for the correct wires for each function.

The 10gauge power cable goes directly to the battery and then the other end goes the amp.  The ground wire is attatched to the vehicle's body.  You need to find a good grounding point that is bare metal and is close to wherever you're gonna mount the amp.  Use a star washer and a short self-tapping screw, but make sure before you drill anywhere that you're not gonna hit a fuel/brake line or go through the gas tank.  Don't make the ground wires any longer than what they already are.

Since it's a two channel amp but you're only running one sub, you're gonna bridge the amp.  All you do is connect the amp's left positive output to the sub's positive terminal, and the amp's right negative output to the sub's negative terminal.  Usually it will have a line or an arrow connecting whatever two spots you're supposed to use for bridging--if so just follow that.

I highly recommend you check out Crutchfield's info about installing amps, and follow their guidelines (i.e. do it in the order they say). Use my help only for specifics not covered in their guide.