Tyres for T5 Multivan

[95vr6]

Hi All, the Michelin Pilot Premacy tyres 235/55/17 103Y my 2006 Highline came with new are 35k old, worn enough to need replacing, and are chipping/chunking off. Anyone else experience this? The Michelin guy said they were not suitable for the car, but that's what it came with!? I have been told there are Yokohama and COntinental alternatives. anyone had any experience with those? I've had to replace two of the Michelins at $495!! and have been quoted $320 for the Yokohamas.
thanks for any tips
Richard

Do you rotate your tyres often? I average about 45-47k out of my Michelin tyres.
What presure do you run at?-----38psi
Would not buy anything else