I miss my Kirkham. It was hot, hairy-chested fun that would leave your ears ringing after 15 minutes. But vision was great in traffic, and you could see everyone smiling, and they could see you.
On the other hand, its track manners were not great when I was driving flat out. Thats how I drive, flat out,...in the rain,...at night
While I haven't yet driven my SPF GT, I've sat in the seat and made engine noises. Its obvious that the trade off for that sleek wind-cheating body is outward vision. And sometimes, I'm afraid to open the door while parked in the garage, even though I've never moved the car since the day I rolled it in there.
Never-the-less, perfomance wise, there is no doubt that the GT will be a step up. With the aircon, I'm not sure it won't be more livable than the cobra was in the summer, and with heat, will almost certainly be more livable in the winter.
My 1 cent opinion (used to be 2 cents, but Obama has decided that I haven't been paying my fair share, so I'm in conservation mode now)