It's a fine motor stock. For tuning purposes, it's a POS
Actually Nyet, while I can totally see why you might have that impression (due to so many incompetent tuners and vendors selling crap for these engines) these motors respond well to PROPER tuning (BIIIIGGG emphasis on the proper part).
Having tuned and owned 2 of them (2004 S4 sedan and a 2005 S4 cabrio) I found that when you uncork them, they're a gem of an engine.
I think where a lot of the misconceptions stem from is the fact that VERY few people know how to:
1) fabricate the proper hardware (i.e. headers, collectors, exhaust, intake manifold, etc...)
2) tune the ECU once the hardware is bolted on
With respect to tuning it, I've literally spent in the thousands of cumulative hours and hundreds of file revisions. I don't exaggerate when I say that I've looked at over a gigabyte worth of logging data, trying to work out the optimal cam phasing and manifold changeover points whenever I made significant VE changes to the car.
Since I'm not on Audizine, I can finally let go and rip on JHM lololol. Having looked at their almighty tune (courtesy of Daz (God rest his soul)) I was amazed that JHM did NOTHING to change the cam phasing!!!!
Why this is, I'll never know, because whenever I challenge them about it on the 'zine, JHM suddenly goes very very quiet.... But what I can tell you from having tuned these engines 1) stock, 2) catless downpipes and 3) w headers is that the optimal cam phasing is VERY VERY VERY different for all three.
For example, with catless downpipes, as I indicated earlier, you need to keep the lobe angles separated much farther into the RPM band than you do with the cats on.
However, with headers, you can introduce overlap much earlier. That said, I found that in order to keep the airflow from flatlining, i had to introduce another 'pump' (i.e. quick retard over 150 RPM) and then quickly drop back into overlap for that last 1000 RPM.
Interestingly enough, you can actually feel it in some gears, almost like the engine takes another gulp of air and shoots towards 7200 RPM.
To make an analogy of it, think of it like body surfing. When you start dropping into overlap, the air pulses become excited as the engine starts scavenging and you get a sudden surge in torque.
However, since your range of cam phasing is limited, you eventually loose momentum and the airflow starts stalling out.
That's when I pull the cam timing back, usually to coincide with an event like the manifold runner changeover. When you do that, it's like going down to the bottom of where you're standing and pushing off into another wave.
Any of that make sense?
In any event, due to the comparative rarity of these engines, there is NO information online about how to tune them. Everything I've learned has been gleaned from other platforms and many, many many scientific journal articles on pulse dynamics and resonance theory.
So while I can certainly see how you may have gotten the impression that these engines were duds in terms of tuning, they actually respond very well IF you know what you're doing; and trust me, that's a BIIIGGGG if...