It's hard to imagine just how badly a set of cheapo ditchfinders ruin the handling of an 8, even in the dry, and can make it lethal in the wet.
Years ago I went along with a prospective owner to look at a PZ that he was thinking of buying.
The car checked out, all apart from the random selection of Durlop, Brigdestone, Pirrelli, Comptinental* tyres.
I pointed this out and the seller said "The car came with those and I don't drive it in the rain, so not a problem"
Long story short, the sale went ahead and the new owner was fairly happy.
He found the handling very different to his previous "hot hatch" experience but assumed that this was to be expected.
He came around a few weeks later to check the brakes as they were "pulling to one side", and asked me to take the car for a test drive.
The thing handled like a shopping trolley, trying to go in all directions except a straight line, and refused to hold a gentle radius on curving slip road without the DSC flashing. The road was cold and damp but no standing water.
We stopped in a layby and I did a visual check of wheel alignment and tyre pressures - nothing obvious enough to explain the handling.
We drove back, carefully, and removed his nice Oz alloys and threw on my old set of OEM wheels with part-worn Michelins.
The whole handling of the car was transformed; the car was stable in a straight line, perfectly predictable in the corners, the braking was balanced with no pull, while DSC and ABS were totally untriggered, where they'd previously been overworked.
He'd spent all is budget on buying the car, so I lent him my wheels for a couple of months until he could afford a set of Vreddies.
He rang me when he got home and said that now he understood all the hype about the RX8 handling, which hadn't made any sense when he first bought the car.
*something like that anyway
and you could play a drinking game with his use of the word 'subjectively' 
but there's a lot of value attached to the wheels of a new car...
