Need input on choosing a Marantz sr5007 or nr1603 to upgrade from old onkyo TX-SV535.(which has not been very user friendly). I currently have as main speakers Cerwin Vega A-10 which have 5/125 watts capacity, and a center speaker Yamaha NC-C125. The speakers/receiver are in a large room. I have Apple TV and a newer TV. with HD (sony led). My concern is that the receiver complement the speakers I have - I may upgrade speakers at a later date. Would the nr1603 model work well with these speakers? The simplicity of the slim line model appeals to me, but it does not have as many watts as the 5007. II want to not go over $850 on a receiver. I originally was going to buy a sound bar for the TV and decided it best to replace the receiver and use current speakers- later buy rear speakers possibly a sub. I am new to this site, do not know much of audio equipment, but like to listen to music. Thanks for any suggestions.