Doh! Sorry, For some reason I read "JVC" and not "DVC".
Wire either in
Series: amp positive output to the positive input of the subwoofer, then from that terminal's negative to the other terminal's positive, then from that terminal's negative to the negative terminal of the amp. This will reduce the load (amperage...in ohms) that the amplifier will see twice the number of ohms oof one voicecoil's rating. In simple terms, if you have dual 4 ohm voicecoil sub, the amp will see an 8ohm total load.
in Parallel: piggyback the positive terminals together and the negative terminals together and plug them into the amp. This will half the amperage. Two 4 ohm voice coils now show a load to the amp of 2 ohms - which means you can effectively push twice the power of the amp into both voicecoils. This can lead to overload on the amplifier and if you are running a stereo channel in mono on the amp, then wiring the sub in parallel, you can drop the load down to 1-ohm as seen by the amp, which is a load that some amplifiers can't take.
As for the stereo...
Track the yellow wire on the wire harness for the CD player. Make sure it goes to an always-hot lead. Look in the fusebox or tap off something that's always hot (sometimes the lighter is always hot) nearby with a proper T-tap. This will solve the memory loss problem.
The red wire of the stereo will trace to an ignition-hot wire.
Use the blue/white wire to run to the amplifier's turn on power.
The manual for the stereo *specifically states* that you will not run the always-hot lead through the firewall and direct to the battery. You will short the wire casing and cause a dangerous short.
Run RCA cables from the rear of the stereo to the amplifier. Using good RCA wires is VERY important - you want something that is shielded very well. This is the core signal from the amp to the stereo and it is very receptive to noise introduction.
Do not run the RCA cables near power wires if at all possible. Definitely do not run them over or with the power wire back to the amplifier. I suggest running all speaker and RCA cables down one side of the car and all the amp power wires (and turn on leads) down the other. Make sure you're not running the RCA's down the same side as any other car power wires. The center of the car is always a good bet.
Always use good, solid grounds and scrape all paint off the grounds. Bad grounds are the #1 cause of noise and interference (alternator whine). The #2 cause is running RCA cables or other signal cables near power sources.
Ground isolators can reduce noise in home stereos - I've never needed to use on in car stereos because I follow the steps above.
Don't skimp on power wire for the amp - buy a kit from the store. See if you can borrow or rent some Greenlee Knockout Punches from the hardware store to cut the firewall hole if you can't find a place to run the power wire.
All of the tips above are things that I've picked up along the way. Follow them and you should be very happy with your end results.
If you halfass your install, you will have halfass sound or destroy your speakers/amps/equipment. I can't emphasize how important it is to spend the extra time to do it right
Go get a good pair of crimpers to do the job right -use butt connectors to join wires. Always tape off any connections if you don't use butt connnectors.