I've run a lot of tyres on my Commodores and E3. Bridgestone 050A's, is used to rate as the better tyre of the OEM bunch, but decided to change to Conti's (5P on the front of the HSV and 6's on the rear), and whilst a good tyre when new, were terrible by the time they were half worn. To the point where I got rid of the rears as I lost faith in the car at highway speed in corners (I used to drive Sydney to the Gong and back 5 days a week). The back end would shift sideways on anything other than perfect surfaces. The spare set of Contis are now on the daily SV6 and I am just chewing them up to get rid of them. They're struggling to handle the power of the V6 even.
I went to PS4S on the rear of the HSV and they're as sticky as and feel very reliable. Mileage, I can't comment as I've had some work done on the car now and it doesn't get out much anymore, but when it does, it cops a flogging.
I still have a set of RE050As to go one the SV6, but after that, it will be PS4S on anything I drive that they make a tyre for.