I have to call BS on it affecting QS. It would be too easy to manipulate.
Their conversion optimization does kinda kick-ass before they slap you though...
Speaking of slap, I got some really good info from a very reliable, and HUGE google "partner" - Basically they have 20K+ google accounts and I had them run a bunch of queries to figure out at what spend limits accounts get slapped at, etc... if there was/is any correlation (and there is). It's the kind of thing that you can't out on a public forum, nudge nudge.