Hi Shaun

I upgraded a 561 (on par sonically with the 565 according to some fellow hikers) to a 568.1 using 18 bit 5000s and found it to be only a marginal improvement. Of far greater value was running the 561 via a 518 to the 5000s. So much so that I bought another 518 just to put between the 561 and the 5000 centre. Unless you were going to upgrade the speakers to 96/24, you won't really get the full benefit of a 568. That said, used processor prices seem a bit all over the place at present, and you might find that there's not much difference in cost between keeping the 565 and adding a 518, or selling the 565 and buying the 568 (no 518). Hope that's of some help!

Cheers

George