Being in Houston, i would not need to change wheels for summer and winter. One set would cover me year round. As i stated before, my concern with the T Sportsline is that Tesla will not fix any issues that they deem are caused by the wheels. They even said they wouldnt align it, which is why i was leaning towards the Arachnids. Now, i have gotten two reports of mileage. One at 25k and one at 6500 miles. Quite the stark contrast. I wish Tesla would offer the Arachnids in a 19"!
That is really weird to hear... sounds like your service center needs to be "corrected" (sorry - had a flashback to The Shining and couldn't resist).
I put on the black turbine T Sportline wheels within a few weeks of purchasing my Model S, and my local service center has had zero issues or comments about using aftermarket wheels (outside of "Wow, the black rims and the chrome blackout looks great!"). Not only free rotations when I stop by, but also did the standard alignment on my 25k service.