Michelin has specifically recommended against mixing and matching PSS with PS2 . The difference in performance is significant enough that they are concerned about throwing off the balance of the handling.
They should bring the PSS to your front size, but have not given a timetable for that yet.
To credit the forum, click through one of the banners in my signature and the top of the page, or call me direct at 877.522.8473 ext 660. Email:firstname.lastname@example.org