decided to finally give up with my Concert headunit, and get a new after market one. Need a bit of help with the wiring at the back: theres lots of blocks of wiring to the left of the system, one brown thin wire in the middle, and a big black lead to the right... now, im thinking the big black lead was for the cd changer (not there anymore), the brown for the aeriel? do the others plug nicely into an audi specific ISO block, so I dont have to do any rewiring? how much do these cost? thanks!