you can apparently get the 860s in the following config :
295/30 R20 101W XLWinterContact™ TS 860 S
Not sure about stock levels though but I'm sure a decent tyre fitter can order your tyres for you without issues though they may take a while to arrive.
in terms of the alpin PA4 , so far it is a bitter sweet experience :
bitter:
- we've had double figure temperatures a lot and the tyres are clearly out of their comfort zone in 12 to 14 degrees. the steering feels super heavy and rolling resistance is very high in these tropical temps. probably the same for most winter tyres in such warm climate
- for a set of tyres, I dropped 1.1k including fitting and storing and excluding my second set of rims. At that price, common sense would dictate driving sensibly, but , no. I drive in sport plus mode everywhere and in cold temperatures , the tyres are great, in warm temperatures , I've shredded those tyres far too often with a heavy right foot. totally user error, can't blame the tyres. but I'm not sure how many winters the rear tyres will last as a result of my foolish driving habits.
-the wheels can't handle more than around 0.7g on corners , but at least the limits of grip are well communicated and progressive.
-steering feel at warmer temps at centre is not ideal , steering feels really heavy.
- stopping distances are longer but you soon adapt to this. so much so that I don't notice any more. it
sweet:
+I haven't got an E63s with its ridiculous power but when it is sub 7c, in a straight line, these tyres will grip the road like Velcro. I feel like I have an awd car a lot of the time even though I don't.
+hardly had any wheel spin in the cold.
+ decent heavy rain performance , note though in standing water , there is a bit of aquaplaning but again this isn't an issue if driving normally
+ excellent icy road performance
+ the tyres are more comfortable than the MPSS tyres they're stepping in for during the winter
+ as long as you're not pushing high g forces on corners etc, these tyres are very confidence inspiring. they are definitely safer than MPSS tyres in the winter for sure. I can put my foot down a bit at roundabouts and junctions and not have any traction issues .
summary :
PA4s are great tyres for the winter. they've really made a massive difference compared to the MPSS tyres in colder weather.