YOKOHAMA S221 are fitted to my MY11 SV6.
They are without the worst tyre I have used in the past 13 years.
My previous Commodore; VEII Police Pack FE2 etc was fitted with 225/50-15s, Dunlop A4 LeMans and then Bridgestone G3. It was a delightful car to drive in the windy stuff, it steered beautifully will the right balance of steering response and feedback.
As a windy road drivers car my SV6 has been a shocker from day 1, mainly dull steering response and tram-lining at conventional/city speeds. Push it on the highway and, once the spoilers started loading the suspension the steering response improves. It has had a wheel alignment (no improvement), and the 5 wheels are rotated at each service (a worthwhile investment that spreads the wear around) There is no value in having a brand new tyre that has been paid for sitting in the boot not being used.
Last month I drove a MY13 SV6 on Bridgestones and it is hard to believe it was the same chassis as my current car. It steered as my VEII did and as I expected a SV6 to.
I would not encourage anyone to buy Yokohama S221 tyres.