I have just purchased the Kenwood KDC-MP6029 with internal 4 chan 50W mosfet amp. Will i notice much sound deterioration if i run my front splits and a sub off of the RCA's through an amp, but also run my rear fill 6/9's rear fill speakers off of the internal deck amp?? The instructions do mention best sound is with the internal amp selected to off if running off the rca's.