I know the Plus 8 differs somewhat from the Aero 8, in that it lacks rear end mass, but I find that on the "wonderful" roads of Wiltshire once above about 40mph it simply ignores almost all road imperfections, at lower seeds it can be a bit crashy.
The only imperfection that catches it out is a bit of subsidence on a C road near home where there is a slight dip followed by a hump: the rear end tends to bottom out as the hump causes it to compress. Almost as if it is under damped. Mind you this only happens at about 70. The front end is utterly untroubled.
The Merc E350 Sport doesn't like it either!
I suppose slowing might help....
