I'm in exactly the same boat as smudge_don, with the same car on 92 rated Bridgestones fitted by the previous owner. The strange thing is that the Bridgestones don't seem to be that cheaper than the equivalent Contis, so they've paid the same money for an incorrectly specced tyre.
For the 2.4 Q4, the maximum allowable loading is 2210 kg total, with 1300 on the front axle, and 1100 on the rear axle (from the owners manual).
For 96 rated tyres, the weight loading is 710kg, or 1420 kg per axle, so the maximum weight loading is comfortably accounted for on either axle.
For 92 rated tyres, the weight loading is 630kg, or 1260kg per axle, so you are inside the maximum allowable on the rear axle, but outside the maximum allowable on the front, by 40kg.
So the question of how 'safe' the tyres are is a question of how much additional weight you put in the car to get near to the maximum vehicle weight. The weight of the car is 1690 kgs with fluids (ruddy fat knacker
), so 1790 with me in it (sadly). Still 420kgs away from the maximum weight loading. As 99% of the time there is only me in the car, the Bridgestones should
be fine for that sort of driving.
I'm on winter tyres at the moment, but when the Bridestones go back on in a few months time, I'm inclined to avoid piling four passengers and a load of luggage into the car, until the tyres wear out and I replace them.
IMO the other comments in this thread about insurance are entirely correct, and I'll be taking it quietly until they get replaced.