quattro question

[jafiluk@acs.ucalgary.ca]

I understand that quattro system will reduce power to wheels that are slipping and
apply power to those that have the best grip , correct?  So it seems one must keep
a steady foot on the gas in order for this to occur, right?

If this is so, what would happen if:  I was driving downhill in very slick/icy 
conditions and there was a curve ahead.  If I took off my foot from the gas, to 
negotiate the curve, would the benefits of quattro be realized?
How would quattro know how to re-destribute power to the most grippy wheels?  Or would
it slow down the wheels with the least grip?

Another topic:  Does anyone have any info on the Tressor (tressor) audis?  
Aprroximately what years were these available?  I think someone on my street owns
one - it looks very nice (completely white-ed out) huge Michelin tires, no audi logos
anywhg
anywhere.  I wonder how it's performance compares to a modern s4/s6??

Jason