Parametric eq install help

I just bought a used audio control eql and a audio control line driver for the sub amp. I have an alpine mrv f407 4 channel amp that will be inline with the eql. I see that the eql has only one input and one output. Won't splitting the cable reduce sq or does the amp have the ability to switch to one input only? Next question the eql only puts out 2volts and I believe the deck will push 4.5 volts is that going to be compensated by the eql control ablility?

Next, I am wondering if the line driver can be installed next to the sub amp or will there be interference? I have the ability to install it in the dash but I won't be able to adjust it there. The line driver increases voltage up to 7.5 volts I believe, is this ok for the amp which is a MTX 1000d? 

The EQL is a nice unit, even if it is a 20 year old design (thus, 2-volt outputs.)  It is a stereo unit, meaning it is designed for use with 2-channels only.  I do not recomend you try to use y-cables to control four-channels of your amp.  Connect it to the front channels only since this is your main soundstage.  If you want 4 channels, you'll need additional gear.  Do you have the owner's manual?  If not, download it from the Audio Control website and be sure to follow the directions to level-match this to your HU, then setup your amp input gain appropriately. 

As for the line driver, why do you think you need this, and why are you planning to use it for your sub amp?