If you can find fresh XWX's for $200 today, buy 'em. Looks like they are up to $400 each now, plus shipping and mounting.
Michelin XWX
The 195/65-15 is a good alternative size, but choices are dwindling there, too. Tire Rack only shows 4 non-closeout tires left today, 2 Pirellis, one Goodyear and a Kumho. From a sidewall appearance perspective, I prefer the simple look of the P6000 (which is actually N-spec for Porsche). But that one is pushing $200, as well. The Goodyear is priced right, but the sidewall is a bit too flashy looking IMO.
Hard call. How many miles do you drive the car? Do you expect the next set of tires to dry-rot before they are worn out as well? If so, I'd be tempted to pay the bucks for the XWX, just because they look right.
Love the car, BTW. Wish it were mine. I don't think tires would have time to rot if I owned it.