Ok... so ive read quite a bit about this over the past few hours and I have to say im still confused! I have an Audi A3 2004 model with a Concert head unit, just the standard, no BOSE, Ive been down to halfords and got the wiring kit 'PC9401' and after adjusting the wires have managed to get the headunit to come on and work. However, there is no base whatsoever! The old concert head unit sounded much better! There seems to be (like others have experienced) very little power going to the rear speakers... Ive learnt from other posts that the head unit now just powers the front speakers and the rear speakers and sub are run off an amp in the boot... However, all I could do with is a simple solution based on my situation...... do I buy the lead PC9404 instead? And if I do will this solve the problem and provide power to the rear speakers? Any help would be greatly appreciated!