You only live once, and if you can afford it, bite the bullet and buy a Flex.
A Corvette convertible and a Miata both provide pleasurable top down motoring, and of course you can easily justify spending the money on the Miata versus the 'Vette for a summer car. But when winter is over and you fire up that 'Vette for the first time in 5 months, it provides a sense of warmth and power that the Miata simply can't match. You don't NEED the Corvette, and frankly you will probably never get the opportunity to unleash all of its 400+ ponies under the hood, but if you can afford it and you enjoy driving with the top down hearing the rumble from its pushrod V8, that feeling alone can justify the cost.
Who knows, maybe if you had a nicer DA you would do a couple more vehicles every now and then for a few extra bucks on the side. The PC is a great machine, but it's no 'Vette...errr....Flex.