I have a BK XLS200 sub and Orb speakers (i.e. quite small steel satellites). I'm running these off a pioneer slimline VSX-C402 receiver. The orbs cost me about £550 and the sub £275. The pioneer cost me £150. Is it worth me upgrading to the Yamaha DSP-AX750SE? The pioneer does the job, but I wonder if it would make a significant difference if I paid out approx £350 to upgrade to the Yamaha? Would I really notice it? Does the other equipment justify an upgrade? Or is the pioneer 'good enough'? They always say that equipment should be evenly matched? I'm not sure if it's worth it, especially as I obviously can't realistically arrange a comparitive audition? Any opinions gratefully recieved.