us amps install ?'s

1. I am installing a us amps 1000x with a kenwood x890 deck and 15" power hx2 dual 2ohm. My question is can I use the sub-out on the kenwood to run the amp in mono? I heard they had to be balanced inputs to the amp to run mono?

2. When connecting the amp it is only 4ohm stable in mono, I have looked at the wiring diagrahms and noticed 2 different ways of wiring the 2ohm sub from 2 different sites, one is us amps and the other rockford fosgates site. I think the right way is one positive from sub to positive on amp. Then one negative from sub to negative on amp. Then positive to negative on sub. Is this right? I think in the ownwer manual for the us amps website it show only one positive and one negative is used to run the amp bridged. Can anyone with more knowledge help me?

here is the link
www.usamps.com/technical/pdf/owners_manual_2001.pdf

3. Also I never hear of this, what does this mean?
U.S. Amps require a
.DO NOT use ground-loop
isolation devices on the
input of yourU.S. Amp!

4. I tested the amp it works, then as I was unhooking the amp the positive wire sparked on the amp case, the ground was still attached to the amp. Do you think it will still work?

5. The us amps website also says to ground the amp on the car body and then run another wire to the ground on the battery. It makes sense but is it manditory?

6. Should I run the powe wire down the driver side and the rca's in the center and if manditory the negative down the passanger side? Or run positive and negative if manditory down the same side and then the rca's down the passenger side?

thank you all for your help, I know your time is valuable.