Quality of new receivers V older ones

Guys,

I have an existing AV receiver (a 2006 Yamaha RXV2600) which at the time was of the order of £800 and came with high quality components - compared to the £300 ones back in 2006. Reviews said you could really tell the difference in build and quality - and indeed in my home cinema setup it still produces excellent sound, though clearly at 720p the video is outdated.

I am about to buy an additional AV receiver, probably a Yamaha RXV671, which I think I can get for about £450 from RGB. I am going to connect it to my PC for a good (by my ears) 2.1 PC speaker setup. I expect to use B&W CM1s and ASW675 sub.

Question 1,  Clearly the new receiver would have more up to date features, but in terms of the 2.1 sound generation (that is all I want it for), has the quality of new receivers moved on such the sound from the new receiver will be as good as that from my older RXV2600 with its stated higher quality components and quality?

Questoin 2; Will the RXV671 drive the B&W CM1s WELL since the CM1s have an 84dB sensitivity which, I am told, makes them hard to drive. Again, the old Receiver did this well - I think it is something to do with the voltage (or is it current - not sure) output from the Receiver being at a higher level than for some machines. When talking AMPs to the likes of Phase3 shop they recommend Rotel AMPS because they output this higher level of voltage - or is it current.

Cheers.

Darren.