As others have said, it's not just the road conditions but also the ambient temperature. I bought new all-season tires right away after getting my Z51 C8 and in my case, I installed them on the same rims that came with the car. That allowed me to drive until November 27 last year (it was a warm Fall) and start driving March 1 this year (daily) which admittedly was a bit early but OK when driving carefully in the Edmonton area.
I sold the summer tires that came with the car, to a member of these Forums, with less than 250 km on them (thanks again Zedaholic, for a ++ smooth deal!).
If I had to do it again, I'd buy the all-seasons before taking delivery of the car, then have the dealer replace them, so there'd be "zero" miles on the tires, making them arguably more valuable and a "sure sale" since they'd be "new". Or if your dealer has no shop/capability/desire to swap tires, I'd line up a place and drive directly there after picking up your car. ****Be sure to stay with your car at all times especially when you're still w/i the break-in period, to ensure no one mucks with it.
If you shop around, you can find Michelin OEM all-seasons at a much better price than from a dealer...perhaps from your local tire shop, or from a GM on-line parts wholesaler such as (in my neck of the woods) BuyKippScottGMParts.ca, where you can pick up from them rather than pay for shipping.
As for replacing rims, you have a ton of choices. I had good dealings with MRR Wheels out of California for some good forged rims. They're used to dealing with Corvettes, have reasonable prices, a great selection, and help out with cross-border shipping costs.
Good luck, whatever you decide to do!
