I recently added a Harman Kardon Signature 2.1 amp to drive the Infinity IL-60, IL-36c, and rear bose speakers. The diiference in sound as compared to my older Kenwood 2 channel amp( 50 wpc) is amazing. The question is " Is it okay to use all five channels of the amp and use the receiver as processor? Or use one or two channels of the receiver to ease the signature amp. Also with this setup will buying a pair of infinity IL-40s for the rears be an improvement over the double cubes and the bass module I have now? I will appreciate the input.