not being technical minded .......
would it make a great difference to my factory fitted head unit and is there much work in fitting it ?
don't worry, i wouldn't be fitting it, would have someone to do that so no risk of the CC blowing up

it'll certainly give you a lot more sound but it'll also blow the crappy factory fit speaker units, the amp is really designed for some hi-watt speakers such as 6"x9" or 1 or 2 two subs, i was running 2 12" subs on me parcel shelf in the pug 106, it rocked the car good and proper
it will work with your factory fit head unit as it's got low level inputs which mean the speaker wires from your headunit go to the amp FIRST then on to the speakers SECOND.
it'll take about a couple of hours to fit, you'll need a amp wiring kit tho.
the 2 phono cables MAY fit as i didn't know i still had them or i would have tried to fit them in the ole CC although you'll only need them if you change the headunit
hope this helps