Here's an update: Things ended up working out different for me. I traded my 2 1230Ws for 2 1030Ws which is what I really wanted in the first place but couldn't find.

I built to separate sealed enclosures (@0.75 ft^3 ea.) to face towards the rear of the trunk and to sit on either side of the rear seat pass through. The boxes are built to sit right against the back of the rear bench seat and I have positioned my two amps in the 2 rearmost corners of the trunk (behind the tail lamps).

After thinking about it this setup was the most practical for me. It took up the least amount of space, added the least amount of weight to the car, easily allows me to remove one of the boxes to fit my mom's wheelchair in the trunk if I have to, and keeps the rear seat passthrough unmodified and fully functional. It was also the cheapest, important for a guy still in school.

It took me all last weekend to decide where I was going to put the amps, build the supports, design and build the boxes. Everything is roughed in right now and I pretty well have my whole trunk availible! So far I'm very happy with it. Nothing is carpeted yet. I have to put the backs on the boxes tonight as I sealed the front and side panels of the boxes last night.

This weekend is going to be busy... I have to carpet the boxes and amp supports, do all the wiring for my sub amp and new 4 ch, and install a pair of Infinity Reference 6.5" coaxs for the rears which I picked up to match my Reference components up front. Its jobs like this that makes me wish I had 2 sets of arms. Or at least a buddy who enjoys doing this stuff as much as I do lol.

My hope in the end is to have the cleanest sounding system I've ever had.