Stelvio QV my20
Why get a set of wheels? Get a set of tyres and just swap them. You get to wear your pretty stock wheels all the time and you know your tyres are balanced twice a year. Hypothetically, If your summers last 20k, the split sets will last you 45k (22.5k each) because summers wear worse in the cold (more skipping less rolling because compound is too hard). So if you will wear through more than one set of tyres during your ownership the only cost is mounting but that also means you balance your tyres twice a year so they drive and wear better.I have to confess I did notice a difference in sub 7 degrees in wet conditions in my 159 in the winter. Could be a placebo affect I accept. I cannot justify paying for a spare set of wheels and tyres on the Stelvio just yet though.
In terms of feeling the difference 3-10c (typical winter weather) is really a crossover area. They would be similar performance to summers in both wet and dry so the perceived differences could be tyre wall stiffness difference or softer tyre compound of the winters. Also if you move from latitude which is more road and comfort to something like pilot alpins or scorpions which is more sporty and equivalent to PS4 or pz4 summers they may feel grippier than your comfort summers in 5-7c but that is not like for like swap. Where you will start feeling the real difference is approaching zero (esp on cold tyres) and also when you go to any true winter surface like black ice on early morning drive or slush or compacted snow - it’s night and day difference as summer can just give with no warning and if you are not 100% dialled in the repair will be more than a set of tyres plus all the psychological trauma. On any inclines it’s magnified. It gives you the confidence not to worry.
The only time they underperform is on the dry surfaces going into teens and driving aggressively - they overheat and become squishy. But if it’s a good tyre it will lose grip progressively - you will feel that same as you feel lower grip on any tyres in the wet and just drive less aggressively. But we are taking freak hot weather in winter and dry. In the wet with extra cooling winters can easily go into high 20s with no noticeable drop off.