Battery Relocation v2 (undercarriage)

I didn't want to hijack MikeyMike's battery relocation thread, since the method I'm going to try is different and probably applies to I4 models almost identically.
Aside from that, I'll be relying on you guys' collective experience on this, so this thread will be more of a project journal than a walkthrough until it's done.
In return, I promise to take lots of high-res pics of my car's naughty bits.
I'll be editing the hell out of this post to make sure the information is as accurate and efficient as possible. After all, I wouldn't want someone to try it the same way if I screw this up.
(Don't worry though, I'm not scared of being called out on my mistakes.)

What I'm looking at, is chopping the positive terminal currently connected to my battery (and going to the starter and fusebox,) connecting it with some sort of coupler, and attaching it to a wire of equal gauge that'll run down and away from anything hot or sensitive to heat or electrical interference. Then it'll run along the undercarriage and to the trunk, where the power distribution block and battery (or batteries) will be mounted. That cable will connect to my battery with a two-output terminal (Stinger probably) that'll split off into the Stinger power distribution box I've got coming in the mail.
I wanted to run a wire to the front from the output of the PDB, but then I'd have a problem with the fuse. I don't know if there are MIDI fuses that go up to the amperage range that starters use, and I don't want to just bridge the connection when I could just bypass it.
The negative terminal of the battery, i'll just connect to a sanded-down point on my chassis in the trunk, no fuss.

My biggest questions at the moment are;

What gauge wire goes from the battery to the starter/fuse box? 2 or 4-gauge? (Edit: Took a look on my lunch and it looks like 4-gauge to the starter, and 6-gauge to the fuse box.)

How should I go about connecting that wire to the one that goes under the car? Would something like this work if I put some heat-shrink over it?
http://www.stingerelectronics.com/productDetails.aspx?delineate=503&CategoryID=45&ParentID=31
...Or should I just replace all of the wires?

Also, what type of conduit or wire loom should I go with? I'm trying to research it, but I can't seem to get good price figures or part comparisons.

u could upgrade ur wires using 1/0 guage wires. theres a diy thread called the big 3.

if you are going to relocate your battery, you won't be able to do the big 3. since the big 3 is for grounding only.

r u sure? cuz wires is just wires.

why do you wanna run the wire under the car? I would be highly concerned about weathering after awhile,even with wire loom..wouldnt be alot easier putting it through the grommet in the fire wall and route it under the carpet to the trunk?

Thats how Im doing it anyways;
have a stinger distribution block that imma attach the 2 wires coming from POS ter. to the 2gauge wire running to the trunk..

then for extra precaution run another 2g ground for the transmission ground taken off after the relocation.*neg. terminal connects to the core support and top of the tranny.*

I took a look at the underside of my car, and noticed there was a cap on a hole in the hollow structural braces that start just behind the front wheels on each side and go down the length of the car. It looks like I can use that as a conduit through to the back. I have no idea what might already be in there though. I'll take pictures when I can take a closer look at it.
EDIT: Scratch that. There are bolts that go through it at a few points. I'll have to run the wire through my own modular conduit or wire loom.

As far as why i'd go down below, I don't like the idea of so much electricity being inside the cabin.
That cable is connected to a 750-CCA battery on the thick positive wire, and connected to the alternator through a 100A fuse on the thinner one, if i'm not mistaken.
If anything went wrong with the wire breaking on the outside, i'd probably have to jump my car with this;
http://www.thinkgeek.com/gadgets/travelpower/962e/ once or get it towed home and get it fixed ASAP.

High amperage wires gone wild inside the cabin, you can have fire, injuries, etc.
Aside from that, I tried looking for good ways into the cabin through the firewall, and didn't like how close it was going to be to me through the driver-side grommet. There's another hole in the firewall on the passenger side, but it looked like it would come out behind the glove compartment by the passenger airbag, and the wire inside the engine bay would be right above the rear exhaust manifold.

I have a low-profile three-ton service jack and two-ton jackstands, and doing it from below seems easier than taking apart all my panels and tearing up my upholstery to hide it.

I purchased the following parts earlier today;
http://www.hifisoundconnection.com/...id/0/SFV/30046/order/desc/order_by/sell_price 20 feet

http://www.hifisoundconnection.com/...id/0/SFV/30046/order/desc/order_by/sell_price

http://www.hifisoundconnection.com/Shop/Control/Product/fp/vpid/5826389/vpcsid/0/SFV/30046

http://www.hifisoundconnection.com/Shop/Control/Product/fp/vpid/3920278/vpcsid/0/SFV/30046

http://www.hifisoundconnection.com/Shop/Control/Product/fp/vpid/1557424/vpcsid/0/SFV/30046

Due to pricing issues (the price of 0-gauge Stinger cable made me wince) I'll assume 4ga wire will be sufficient for now, although I may upgrade it to 00ga when it's time to start piling in the LiFePO4 batteries...

But that's a topic for a later time, when I have way, way more cash to play with.

i dont know if it will make your life easier with hiding the battery, you can get a dodge stratus battery box since its the same size as the accord and Tuck it under the frame/fender to where the resonator was. All the resonator bolts and brackets are there so mounting it would be easy and it would eliminate taking up engine space for starters, and trunk space, and you could use the same Battery cables with out modification, just tuck them

thats what i was gonna do but didnt get started yet

^ Your method would not work for people running, or wanting to run a CAI or turbo.

...Getting a little nervous about what could go wrong. I'm not worried about my ability or anything. The parts haven't showed up yet, but that's not a big deal, either. 4ga wire should be fine, right? It's the same gauge as what's already connecting it, but it's going to be much longer now.

On the other hand, the positive wire currently connecting the battery is partially exposed and oxidizing and the negative is a mess of half-exposed unwinding green copper rust, so if it's working fine now as is, I would expect 20' of brand-new Stinger cable to work just as well, at least.

...amirite?

yes to ur last question. should be a better connection with newer wires.