Interesting, just had a look at those Audi's, seem like an interesting engine.
I don't agree that that a 5 valve engine is an inferior engine, it's just a different approach that costs more to manufacture for negligible power gains in factory terms, hence they never got fully developed. The more valves you have the smaller the valve and the less spring tension you need to seal it properly at high rpm and boost. Which means more power :(
The fastest 1.6L turbo FWD drag car in Australia has a 20V blacktop head, and it keeps up with 2.2L vtec 4 valve motors, given the 600cc difference, I think the word inferior - "Of low or lower quality" is a little bit of a hike.