VW-Eurovox Headunit to Amp

Hey, sorry i know this question would have been asked a few times in different ways but i have read over the forums and cant really answer my question

I have a factory headunit in my Golf and i dont want to have to change it over,  it runs into a 8 speaker set; 4 sets of splits. I wanted to run a Boss Audio 4ch 1000w (only using 2 chans) into a 12in Kicker 250W,. I dont have RCA leads on the headunit but i have high level input on the amp. I was told by Eurovox that i should have RCA leads fitted, i am not a sound quality freak but i want a clean good thump. Does it make any difference anyway to the sound quality by having RCA leads fitted?? Wouldnt they just be running off the speaker cable anyway?? Also If i was to wire in some RCA leads how would it work. I have obviously FRNT LFT + & -,  FRNT RHT + & -, REAR LFT + & - and REAR RHT + & - So would all FRONT and REAR NEG go into the one plug and all FRONT and READ POS into the other???

I was just wondering if anyone had had any wiring diagrams on the Mk4 Golf, to do with the Eurevox head unit, or the general wiring in the car eg: where abouts all the wires are run in the car. I dont really need anything on cruise or alarm.

Thanks Heaps