Google Myth - Quality Score
Now there are many components that go into quality score and a lot of mythology that surrounds it.
However one thing does NOT factor into Quality Score.
KW Level Destination URLs do NOT factor in. (This was confirmed to us from a tailor presentation Google did at our offices last week to clear up the myths in marketplace about quality score.)
This in their opinion was one of the biggest myths so for those changing their kw level destination URLs, that alone will not alter your quality score.
-Jason