hi, my current setup is denon 1909 with tannoy efx 6.1 speakers i am looking to upgrade to MA Apex A10 i cant find a good deal on A10. but what i found is 2 MA R90 speakers (one pair) 1 MA A40 for centre i am planning to buy a sub from BK electronics XXLS400 i am looking for 2 more speakers does this combination work? can i use the above with my Denon 1909 or should i upgrade it too? I have my eyes on Denon X2400 but short of budget for now. any suggestions about the speakers with 1909?