word, even over mild standing water at 80kph, the car wriggles and jitters like the HICAS is going off its nuts. The rears were aquaplaning, not fully, but enough to ensettle the rear end.
On the F3 going home one night in the wet at 120kph, driving over a wash of water (water coming from one side of the road to another due to the camber of the road and gravity) the back will lift up entirely and sit itself down again pointing a few degrees away from the direction of travel making you shoot off into the other lane before bring it back under control. Scary stuff and I always slow right down to 80kph right awy untill I get my kajhones back D:
Fresh tyres on the back makes the car feel so much better, like it was dry.
I think its most likely because one wheel will aquaplane first, making the toe-in on the other wheel push it, then the other wheel will plane, and the same goes for the other wheel, making you shake around.