What happened there? At about the same time at Perry's autox4u.com forum someone has posted a link to the Autocross performance handlbook, which provided me with a partial explanation: the important reminder is that the only thing adjustable in the single-adjustable Konis is rebound. The compression rate stays fixed. That book also says that the reasonable adjustment rate for Konis is between 0.4 and 0.6, anything higher goes disproportionally stiff.
If you adjust the rebound too harsh in the rear, you get the wheelhop under acceleration. It develops because when a wheel jumps a little, the stiff rebound rate of the shocks don't let it get back to the ground. Now, when you get the front rebound rates too stiff, you end up with a symmetric thing: a wheelhop under braking. Once a front wheel hops, it gets locked up and immediately wears into a flat spot. No wonder I've been flatspotting the tires like crazy during the last 2 years.
Then I've tried the same stuff on Camaro and it worked too.