Sounds like an excellent way to celebrate your retirement!

If the SC is the one you want, that's the model you should get. It's a lot of money to spend so I would recommend fastidious research on the good and bad things about that particular model so you know exactly what to look for. It makes sense to have the car inspected before purchase or to buy from a Porsche specialist who know the cars inside and out.

Annual maintenance shouldn't be in hundreds not the thousands, although it makes sense to keep a car fund set aside for any unforeseen larger issues. Have the car inspected annually and you should catch small problems before they develop into something bigger.