Couple of test points from a tech paper by VAG.

- braking tests showed up to 23% improvement in stopping distance due to the
syncro 4WD system over same vehicle in 2WD.

- a difference of greater than ~5 RPM across the coupling will initiate lock
up process.  Such a difference occurs with 3mm tread wear diff. F to R on
175/70/13 tires at 160kph. check those tires/pressures folks.

Tom