RE: moving compressor to trunk
It's gonna be a lot of work, for not a lot of gain. The compressor only weighs a couple of pounds, with the dryer adding another pound or so (I'm guessing). You could probably take everything out of your backseat, throw it in the trunk and get better results.
If you still want to do it, you'll need to run new lines to the trunk, along with all the necessary wiring. This includes the relay wiring and power wire capable of supporting 50 amps - repeat, capable of supporting 50 AMPS!!! I'd recommend running at least 4 gauge to the trunk for this.
You only need to run one airline from the trunk to the original compressor location, but it might be easier to run four. Use a five port block and run the compressor to one port and the four airbags to the other ports. This may take a little creativity to make. The solenoids control which bag is inflated/deflated.
The reason I say it might be easier to run four separate airlines is because the dryer has four ports. Now you have to convert the four lines down to one, then back to four. Four 3/16" compression unions may work better. Since the lines are small, running four shouldn't be much more expensive or difficult. Either way will work, but I'd probably opt to go with two blocks on each end just because I'm not fond on those tiny compression unions, and I don't think DOT compression fittings are available in 3/16".
I think you're gonna find out that it's a real bitch to run the lines and wires. You also need to make absolutely SURE, there are no leaks before you put everything back together. If you are unfamiliar with the air suspension system, especially the fittings, you're not gonna have a fun day.
The only time I would recommend doing this is when you want to start controlling the airbags manually, or adding a small reserve tank and/or bigger vent valve.
Kale