Well, not much really. Worth is only the amount that someone is willing to pay, and unfortunately SSP's don't pull much value unless you're a collector and they're near service condition, and since mine has a Pacecar nose and tons of other goodies, it's not much SSP anymore aside from the history and the buck tags.
A buddy of mine has a '86 (I think) ASC McClaren convertible Capri. They made them from both mustangs and capri's.
It's not really clear from that picture, but like someone else said, the windshield is angled back noticably, I think around 15 or 20 degrees. The interior in my friends was also different I believe, it had different leather seats and I'm pretty sure they had McClaren embroidered or something.
I think they also came with modified suspension, but it's really been a while since I've looked into them. Other than my friends, I can only recall seeing one other McClaren driving around, and it was a Mustang.
That definitely does look like it was taken at the Roundup. I park in that lot every day for school. Well, for 2 more weeks anyways.