Hi John,
 
I don’t believe that you’ll find any Michelin N-rated tyres in those sizes, especially MPS4S or MPS5.
 
If you have the Porsche Extended Warranty then you have to have N-rated tyres for the warranty to be valid, so you’re stuck with the approved Pirelli and Goodyear tyres. If your car isn’t under warranty then you have a free choice, and although the MP4S4 appears to be the tyre of choice the Goodyears have their supporters if you’re not keen on the Pirellis.
 
Jeff

+1 on Graham’s comment about using summer tyres during the winter. Quite a few owners buy a set of wheels and tyres for winter use to avoid the faff of having to swap tyres.
 
Jeff

Unfortunately I don’t have any experience of winter tyres John, so can’t provide any direct advice, but this link may be of some use:
 
https://www.porscheclubgb.com/forum/tm.aspx?m=1067050
 
I would think that winter tyre offerings from the major players - Goodyear, Michelin and Pirelli - would be a good choice, although I’m sure that there will be many others.
 
I don’t recall anyone on here mentioning that they’ve fitted all season tyres for year-round use. Although I’m sure that they would be good for winter use, it’s likely that they will compromise handling for summer use … which surely is one of the main reasons for purchasing a sports car! The fact that Porsche currently don’t have an N-rated all season tyre indicates that they agree.😀
 
Jeff

Michelin Cross climate tyres or their competitors (eg the Hankook Kinergy 4S) are great.
On normal shopping cars. 
Not for sports cars I’m afraid. 
I have the Michelin Alpin PA4 N0 on 19” wheels, these were supplied as package by Porsche.  

Greenman986S
Depending on when your car visits your OPC, does it really need N rated winter tyres?

only that it’s surely better to have winter tyres that have been developed for your car, so you know will work well in it. 
Got to be better than pot luck?

Greenman986S
Maybe....but the OP doesnt rate the  Dunlop SP Sport Max GT N0....
 
we all make our choices 

To be fair he doesn’t rate their performance on snow

Pirelli P-Zero tend to get somewhat slated but my experience (on 20" wheels) is that the original N0 were poor but the latest N1 are completely different and much better both for wet grip, particularly when cold, and also for ride. Whilst the recommendations above to use winter tyres in winter is the right one, particularly for a daily driver, I was caught out coming back to Derbyshire from Wales about 18 months ago on "summer" tyres in a massive snowstorm with lots of closed roads and a completely snow-covered road surfaces for several hours of driving, albeit rather slowly. I was actually quite surprised that I was able to keep going, steering (and stopping) in circumstances that I thought would defeat my Pirellis completely. My first Boxster was a 986 daily driver - that was very scary in snow on the then current Michelin "summer" tyres. I have had Goodyear Vector 4Seasons on a previous Audi Q3 which were completely amazing up the Cat and Fiddle (if you know that) in a blizzard - just ploughed through everything without losing grip at all, but all-season tyres are not suitable for Porsche sports cars.
I would concur with the above that if you want the best for winter, buy a set of winter wheels and tyres, but beware buying cheap ones off ebay - many look unused but are ancient tyres which should be on the scrap heap. If you buy "summer" tyres (such as Pirelli) make sure you get the latest N rating for your wheel size, because eg N1 on 20" wheels are not the same as for 18" or 19" which may have more generations of N. And if you buy Pirelli, don't forget the PCGB offer (see PP ad and discounts on web site) which only applies at OPCs and Pirelli Performance Centres.      

John52
The Dunlops were truly hopeless in the snow, hence my need to find a solution before the next winter. A set of winter tyres is the obvious way to have total reassurance in cold conditions but if I stick to the convenience of having just one set of tyres could anyone advise if the Pirelli and Goodyears could be used in the cold. I can’t imagine they would be as useless as the Dunlops were & I would imagine there must be many Boxster/ Cayman owners who have used them in the cold with some success. To me I think it is unacceptable that Porsche sell these cars with Dunlops knowing that in cold conditions there will be very limited braking from them. 

 
I assume that it`s your daily and that you `have to` use the car in such conditions ?
 
Cold conditions and snow conditions are quite different, you can expect - within reason - Summer tyres to manage the cold but not the snow 
 
Have you tried turning the traction control `off` in snow conditions, it `usually` helps ... 
 
 
 

MrDemon
not sure where you got the 7oc from this is for a cup2 tyre a PS4S still outperforms a winter tyre at 3oc.  and P zero are utter **** tyres lol imho.

Where did I get it from? Well Porsche say:
 
The driving performance and comfort of summer tyres deteriorate at temperatures below 7 °C. Porsche therefore recommends changing to winter tyres when temperatures fall below 7 °C.
 
And Michelin say:
Summer tyres are designed to be used during warmer months when temperatures can reach up to 40°C on occasion or even extended periods of time, or throughout the year in places without winter weather. With a shallower tread pattern and a stiff, sticky tread compound that offers excellent grip on dry and wet surfaces, summer tyres are specifically designed to deliver optimal performances in temperatures above 7°C. They maximize precise handling and make sure you’re as stable as possible when turning corners or braking.  
 
And for clarity Michelin class the PS4S as a Summer tyre. 
 
Now it could be that that you are right David and both Michelin and Porsche are wrong. You tell 'em!
 
Further more it is manifestly complete bollox to say that the current P-Zero is crap. You may have a preference, as I do, for the PS4S but the current P-Zero N1 is a very capable tyre. 
 

Thank you all for your replies.As I don’t want to have the palaver of having summer and winter tyres I have decided to just have summer tyres and not to drive on the days when we have snow. It is too scary to drive on snow with my current Dunlops. Before our next winter I will buy a new set of Pirellis and just accept their limitations in cold/snowy conditions. I wish Michelin had produced some all-season tyres for the Boxsters and Caymans like they do for my wife’s Macan as those tyres provide complete confidence in all conditions.