I know... Initial signs are OK though as I don't drive it any harder than my Z4 80% of the time and I've got it setup with much less toe in than they normally have. I'm using up the Yokohama Advans first which are quite grippy in the dry but poor in the wet and only 240 treadwear rating. Then it will be PS4S in 245/265 rather than the stock 235/255.
Many people will be happy with a bit less tyre performance as most of the time you don't need it. However, that extra few metres of stopping distance or swerve in a corner unexpectedly I'd rather have more grip to call on. In normal driving the feedback and subjective feel of the tyre is also better with those like the PS4 or PS4S.
I haven't tried the PS4S yet but as it's just a better version of the PS4 I know I won't be disappointed. When I went from F1 AS2 to F1 AS3 that felt like a backwards step despite claims by Goodyear that it's better.