civic amp/wires/sub install

Yea I agree, the easiest way to cut the hole is definitely using a circle cutting jig and a router.  But if you don'thave a router or a jig, or don't want to get one, it can be done with a jigsaw.  It's a lot more work but it is still possible

When I do my boxes I use a spray type adhesive, and apply it to both the carpet and the box.  It sticks REALLY well and stands up to heat very well.  I don't have the 3m brand but I imagine it's just as good, if not better, than the stuff that I use.

Also I think it's worth mentioning that a lot of times people only have a very limited amount of material to work with, and therefore they have to use methods that will waste as little of the carpet as possible. But this also means sometimes it makes it harder and more time consuming, that just wrapping the whole box up real easy.

This is the harness you have to use if you have the factory keyless entry....you have to keep the stock head unit and plug it in to the female plug on this harness, and then relocate it somewhere in the vehicle.

UPDATE: my sub came today!!! so, I finished the box, the carpet looks alright (I admit it could look better but I am happy about it) wired up the sub for 2 ohm operation and it is installed in the box. I put in a good deal of fiberglass insulation (sold at home depot, they make small packages now for $4!) because I used 1/2 inch mdf instead of 5/8 or 3/4. next step is to install my amp wire kit - that'll be a trip, and I need to buy an amp. my friend said he could sell me his Kenwood amp for $50, it is the one from last year and it says 350w on it and is 2 channel, is it 2 ohm stable? will that provide adequate wattage to my sub (300w)? 

I'm pretty sure the amp you're describing is either this model, or the previous year's comparable model with identical specs and just a different exterior.  It is not 2-ohm mono stable.

In any case, that amp only puts out 150 watts RMS x 1 channel, and even then it'll only do that when you run it bridged to a 4-ohm load.  As we said earlier, since your sub has two 4-ohm voice coils, it's not possible to wire them up for a single 4-ohm.  Other than an 8-ohm bridged load (which you do NOT want to even consider doing as it will put out even less power), the only way you'd be able to run this sub would be with hooking both voice coils up to a single channel, for a 2-ohm STEREO load on the amp.  This will send 75 watts RMS to the sub, leaving basically half of the amp unused.  Needless to say, 37.5 watts per voice coil is seriously underpowering this subwoofer and I don't think you'd be pleased at all with the way it sounds.

If I were you I'd spend the extra $150 for the JBL BP600.1 amp.   Even at $199 it's a bargain considering how much power you get and how solid and versatile of an amp it is.

Normally I would recommend that if you're on a really tight budget you check out an inexpensive 2-channel amplifier, but the problem is that these only reach their full potential when you're able to bridge them. You can't do that with the DVC sub you have right now;  so you'd have to look for a 2-channel amp that puts out 150 watts RMS x 2 channels@ 4 ohms stereo, and you'd have to hook up each voice coil on a separate  amplifier output channel.  This is something you always want to try and avoid whenever possible.  Also, a 2-channel amp that puts out 150 watts RMS x 2 channels @ 4 ohms stereo is probably going to cost you close to the $200 that you'd shell out for the JBL amp.