From what I've read (in a non-Bose) setup, the front speakers are powered by the satnav, and the rears by the little amp on the plastic sub. Does anyone what the RMS rating for the amp on the sub and the one in the RNS is? I want to upgrade my sound in pieces.. thinking of first replacing the front door speakers with RF or Lightning Audio 6.5" splits (they are around 50W RMS). Just wanted to know if the RNS will be able to drive them without causing problems. The reason is that I want to spend time and see what I can do enclosure wise and make a decent install (like those awesome wheel arch boxes that Andy has made) but am also keen to tinker until I can sort out wht I am going to do with the rest of the sytem. Any thoughts or suggestions?