I currently have a panasonic pl4 tv and am considering upgradin to 5.1 sound. My question is what connectivity will i need on the amp to ensure i can still get the pro logic sound from ordinary tv? At the rear of the tv there are 5 phono outputs for each of the channels - do i need an amp with 5 phono inputs or can i get away with just connecting the L and R channels to the amp? Also, the tv currently has 15w centre and rear speakers - will these sound poor if mixed with 2 80ishW L and R speakers? i.e. do i need to upgrade all speakers or can i get way with just getting the front 2 for now? Any advice would be appreciated.