On OOF, we have the benefit of a vast amount of personal experience of tyres on Omegas. We have also proved quite categorically that tyre tests on other cars is completely irrelevent.
The Falkens on Gixer's car, for example, a very well regarded tyre on family hatchbacks. On Gixer's car - I drove it about a mile at one of the Ashridge meets - plain dangerous. Dangerous in that you cannot keep it between the verge and the centre white line. Slap on my Dunlop SP9000 to test, and its fine. No doubt in my mind, based on my experiences of that tyre on an Omega with a proven "good enough" setup on the chassis, the tyre is simply unsuitable. No idea why, despite spending much time try to find comparisons with other unsuitable tyres.
My own Elite, shod last September with £700 worth of SC5, another tyre that Golf owners rave about, utterly shite from the outset, similar problem to the Falkens, but apparent immediately, not after 1000 miles or so. Fortuantely a short lived mistake, as the fronts came off at 3.5k, because they were shot. The car wasn't even driven hard, because it was too unpredictable. Rears still one, but about spent. Again, no doubt in my mind based on my experiences of the tyres on an Omega that they are entirely unsuitable. Dangerous in fact.
I know Lizzie loves Pirelli. Having used P6000s on Mk2 Astras, Rovers and Omegas, I'd say that the tyre wasn't great, due to low levels of grip, and not a great life. However, on one of our Rovers, the little 25 we owned from new for 12 years, the P6000 was brilliant. Stunning. Tried other brands, such as Goodyear, and the car was rubbish, go back to P6000s and the car was brilliant again. Clearly the tyre worked well on the 25, but not on anything else I've put them on. Why? Who knows.
Tyre tests done on other cars means nothing to us OOFers.
Oh, and for the record, stopping an Omega with A rated wet stopping SC5s in the rain is buttock clenching. Try to turn in the rain, don't bother with the big round thing in front of you.