Need help in choosing an AV Receiver

Sound preference is very subjective. If those are US dollars, those prices are ridiculous. (Judging by what I am seeing, you are not in North America) The Onkyo is particularly overpriced in relation to the other ones listed. That Onkyo model has a history of reliablity problems and has already been replaced by the NR616. Refurbs of it regularly go for $250 here in the states. Yamaha is probably the most reliable of the choices, but the lower models like the 371 and 471 use chip amps instead of discrete amps. Denon's have a rep of pretty good sound quality, often seen as better sounding than Onkyo (but again, its subjective) and are generally a tad more reliable than average. I'd take the Denon 2113 before the Onkyo, especially if its $200 cheaper (I'd be surprised if it has any more trouble driving 4-ohms than the Onkyo). The other model I'd probably look at out of these choices is the Yamaha RX-A810 which is a model from their higher end Aventage line. There are threads for both of these receivers on the forum so definitely read through them.

With that said, if you are looking at driving low efficiency 4-ohm speakers, I would be seriously looking at a separate dedicated amp built for it rather than home theater receivers, unless you can find something like a Harman Kardon 660/760 somewhere.

However, preference only makes sense if there are actual audible differences. As amps, preamps, DSPs, and DACs that is unlikely with modern equipment.

Agreed. For example the last price I saw for the Yamaha V371 was under $170.

Actually all SS amps use chip amps. In some cases the chip is a single chip that is the whole power amp minus a few bulky parts. In other cases the amp is a encapsulated piece of ceramic or metal substrate with a number of chips bonded to it. In other cases there is a messy and potentially unreliable plastic circuit board with many parts bonded to it but open to the air, and some of the parts are themselves a single encapsulated chip bonded to a substrate.

Obviously, the performance of the amp is based on the amp's components and configuration with the packaging taking a big back seat. That is why I always say judge components based on how they perform, not the unimportant details of how they are made.

The idea that all receivers or all receivers except those from a single manufacturer can't drive 4 ohm low efficiency speakers is yet another audiophile myth. Many audiophile power amps aren't any more robust than the AVRs once you get under the covers. Note for example the common but not universal absence of ratings for 2 ohm loads. Furthermore some AVRs, like many of those from Yamaha do have 2 ohm ratings...

The lesson is that all generalities are false, even maybe this one! ;-)

I of course meant IC on the lower Yamaha vs discrete on the higher end, pardon my lazy vocabulary/writing. I should be more careful so its clear. As to whether different receivers sound different or not, that argument can go on forever so let's not start another thread on it. What's your opinion on what receiver the OP should look at?

I'd be surprised if there was any difference in sound between the 2113 and 2313 and I have not read anything to make me think otherwise. The 2313 has a slightly more powerful amp section, but its not a significant difference.

Yes, sound characteristics between the two should be very similar. Regarding the 4-ohm requirement .... if you only plan on average level volumes (eg. -30db), the 2113 would be a good choice, however, if you prefer louder (ie. reference level) movie volumes, you may need to add an external amp and for that the 5007 has a full set of pre-outs whereas the 2113 does not.

No reason they wouldn't.

That's where you are wrong. The question of whether or not different receivers can be spiked in almost no time with some properly-done listening tests.

Believe it or not, the application of good Science can provide superior results to dueling opinions. ;-)

I'd love to do it, but not being independently wealthy, I'm not about to repeat what I did with PCAVTech and PCABX - give expensive (to me) free gifts of knowledge to the world in the name of Science.

And, there's no reason for any commercial entity to spend one dime supporting any effort to develop true knowledge in this area because it runs counter to their salesmanship.

Pick the one from a mainstream manufacturer that has the features they want on the grounds that as far as the basic amplifiers DACs and DSPs go, sonically its pretty much all the same. Yeah they measure different, but so what?

If I was formally researching the AVR market I'd start out by trying to figure out what the alphabet soup in the area of automated system optimization (YPAO, MCACC and Audyssey) means in terms of final listening SQ for the AVR's owner.

Right now it appears that far and away the strongest SQ differences among AVRs are related to the effectiveness of their (generally misnamed and missold) system optimization facilities.

A whole different line of inquiry from my previous comment about AVRs is why pay the big bucks for yet another 2-way system with one or more 5 or 6 inch woofer/midrange(s) and a dome tweeter? (yes I know both these speakers we're talking about now are 3-ways and also have 2-4" midranges)

The Wharfdales are about $650 each, while the fairly similar Primus P363s are $200 each. What do you get for the other $450 each other than name and locality?

I admit it, I'm against both of them on the grounds that floorstanders are somewhat overkill if there is a good sub, which there must be for optimal SQ.

Presumably the midranges give smoother transitions in the area of directivity control through the critical midrange region, and the extra woofer grants a little more dynamic range in the upper bass.

A reason to spend more is that the $650 speakers probably use better components, not just the drivers but also the crossovers. One cannot put $100 of crossover components in a $200 speaker and still make money.