Maybe this has been answered and I'm being dense, but I want to get this answered once and for all, and that's probably going to require at least a semi-official answer.
There's nothing in the errata 1.5 or the current FAQ, to my knowledge. Previously, the answer has always been "Wait for Augmentation". Well, I've read Augmentation and I'm still confused.

The Critical George example on SR4 pg 335 is confusing to me.
How many areas are figured into the full-body calculations? 4 (one for each limb), 5 (including the torso), or 6 (including the skull as well)???
Critical George seems to imply that you take all the limbs and then add the body's natural value as "one limb" into the calculation, regardless of how much meat that actually represents. That method is obviously absurd, since by that method Critical George currently has an average Body of 4, but if he were to get his right arm and right leg replaced with cyberlimbs which both had a Body of 3 (his existing natural stat, and thus the body rating of the meat in those limbs), suddenly his overall average Body rating would drop to 3. Using that method, it's also possible to construct examples where someone can improve the stat in a limb and still have their overall stat drop, so it seems like the only sane way to handle it is to count every limb individually (no matter how many are cyber or meat) and take the average, but there are still problems. Do I really need to worry about the strength rating of my head? Ever? Nevermind that some of these limbs simply don't have the capacity to match high stats (although that problem has gotten MUCH better with customized limbs, you still can't make a cyborg with much higher-than-unaugmented-max because of the limitations of the skull, WTF?). What about partial limbs? Maybe we just need a semi-official account for exactly what percent of the body's performance is contributed by each limb.

So can we please get a clear and final answer on how unbalanced attributes in multiple limbs are to be handled?

It boils down to: if you have a natural Body 6 and you buy an off the shelf cyberlimb that's only Body 3, yes, your average Body will drop. That's what you get for buying flimsy merchandise. Buying a custom cyberlimb (Augmentation) and maxing it's Body to 6 is not expensive and does not cost any more essence or any more capacity. That's Augmentation's fix for the average cybered attribute problem.

Are you sure a cyberskull counts for reducing/increasing average agi and str? I thought it was just the arms, legs, and torso.

I would just use cyberlimbs and cybertorso (but not cyberskull) in calculating average agi, str, and body. I can't imagine the skull adds or subtracts anything from the average body and certainly not to agi or str. If you're trying to tow a bus with your teeth or something weird like that, then the cyberskull might need to be calculated in, but that's a pretty rare corner case.

EDIT: Jaid's edit answers it perfectly.

As to wanting an official errata, feel free to hold your breath, but the last errata was posted nearly 2 years ago and there doesn't look like there's going to be one any time soon. Feel free to spam the developers, maybe they can make it happen before the sixth world arrives.

There was an at least semi-official answer (I think from customer service or maybe a letter to Rob... whatever, my memory sucks) a few weeks ago when the subject came up, and the answer was that a cyberskull doesn't apply to such calculations. Ignore the skull and only the varied stats on the torso and four limbs (5 total) are used.

And yes, if you have a cyberarm that's more vulnerable to damage than the rest of you, that makes you more vulnerable to damage. Weakest link in the chain and all that. It's an abstraction, just like everything else.

I mean, putting 2 points of armor on a cyberlimb gives you 2 points of overall armor, but that rarely gets angry responses. Does that mean abstractions are only okay if you get a bonus out of it, but not a penalty?

A boosted limb should never lower your overall average in any examples. At most, your overall effect is unchanged. The problem with the book example is that people assume (because the book never says otherwise) that the skull is a limb, and somehow ignore it in the calculations. That results in some really rare cases of getting a lower average since you're adding up five but dividing by six. Even when unaugmented. For example (3 + 3 + 3 + 3 + 3) / 6 = 2.5. Get rid of that sixth "limb" and it works just fine.

The book example can eat me.

But if hes eating you, do you use the strength of just his skull? Or do you use the averaged strength? If the averaged strength, is it the average of 5 (body + limbs) or 6 (body + skull + limbs)?

I'm a full-body meal.

I’ll make it simple for you brothers. Let me quote from the holy scriptures. Page 335 and Psalm “Cyberlimbs�…

“Cyberskulls and –torsos are included in this category, though they are in fact shells
rather than full replacements.�

There you have it brothers, the holy scriptures clearly states that they indeed counts as cyberlimbs and follow the same rules. Sure, they are “in fact� shells but the rules labels them as cyberlimbs.

It makes sense if a flimsy skull drops your overall resistance. It doesn't make sense for str and agi, but guess what? It doesn't matter! The rules specifically state that when using a particular limb for a test, you can use that limb's stats - so if you punch with your strong arm or shoot with your fast arm, you use that arm's stats. Overall str and agi actually don't matter in any example I can think of, at least as long as you can use a limb or set of limbs that exceeds your overall stat.

For simplicity I would rule the following:

Single limb action: Firing a gun, hitting someone - Use limb attribute
(Yes, it can be debated that one use more than one limb but it's easier as the limb does the primary work...)

Full body movement: Running, leaping, tumbling, climbing - Use average attribute

Unless you're a GI Joe action figure, you're going to use more than your arm to fight. But according to the book, you do, so following the book's logic, running and jumping would only be leg tests, not full body tests.

Thing that confused me from Aug is for custom limbs. Is the cap based on current Attribute or racial max?

Also is rating three bonus max without cyber torso then be based on current attribute or racial max?

Either way cyber limbs are rated 1-7, with torso are you then allowed to break racial augmented cap? If not then someone with exceptional stat would not be able to utilize up to rating 7.