G'day , just a quick question . I have an 08 BF MK2 XL ute and was wondering if the standard head unit is 4 channel or 2 channel as it standard from the factory with just the two speakers in the front doors. I am thinking of upgrading with a 4 channel amp , 6" fronts and 6 x 9 rears / inline splits from head unit etc if there is output from the head unit for rears. Any info appreciated before I start disassembling