Hey Sleepin,
I've got a pair of of Z8's, so front & rear.
Dunno what BS that salesman's slingin you?
Maybe they are out of stock in all of Australia?
Or maybe he's to slack to admit he can't find you a set?
I've got 6,000 km's on them now and the rear has a flat spot and shows some signs of cupping.
But both my PR2's cupped really badly too.
Weight, suspension, chassis twist, speed are all issues for cupping tyres.
So shed some kilos, get low, stay straight and go hard.