[BIGglaSS]

I'm not exactly sure I follow what you are doing. Sorry, But It's not close to properly set-up.

If you want another amp for the 10", the xc2110 has high level input. You could use the speaker leads from the head unit.

Your current amp has enough power for the speakers you already have.

EDIT:
The XC2410 does NOT have a LPF. Don't use it for the sub.. sorry. I deleted most of what I previously wrote.

However, the Coustic 321QE does have a LPF. Check the owner's manual, you can probably run it bridged and use it for the sub.