I'd like to think that Samsung "learned their lesson" with the crappy DACs in the GS2/Note Yamaha chip.
I tend to think that's they went back to Wolfsson for GT-I9300 International GS3. Amazingly the WM1811 has pretty much the same architecture as the GT-I9000 Galaxy S's WM8994.
I hope they've stuck with Wolfsson, or something good quality on S4 as S3. Many other S3 attributes carry forward, I think due to Samsung becoming more "conservative" in their striving for continued dominance.
I think they know that having 20 "bullet points", compared to HTC's or Sony's mere 18 bullet points, makes all the difference in creating a best seller.
So far, I haven't found any analysis of the teardown(s) or anything showing the audio chip.
I'll guess that likely the Snapdragon variant will have Qualcomm WCD93xx, and that's a pretty good chip IMO that I think only audiophiles will quibble about.
And I'll wildly speculate the Exynos variant will use a WM18xx chip.
Personally, I'm most interested in audio and the FM/combo chip. It appears as if BCM4335 FM/Bt/WiFi(ac!) will be used on all variants, and I think it may even support FM receive this time, instead of the usual dedicated si470x chip found in every other Internation S/S2/S3/Player/Note/Note2 so far.
And Sprint's (& maybe others) tentative payola deal with US broadcasters could mean FM will be possible on US variants for the first time. Or maybe not.