As you can see, to each his own. Now admittedly I don't own an SN95 car, but I am familiar with them in a number of ways. And a car is a car is you understand their differences. I've never owned a Z06, RX7, or MR2 either, but had good to great success for myself and customers in those cars. Marcus has always been very open with his car, and I've driven it many times and with different setups. I've messed around with a local customer's GT who had a pretty good showing in KS last year having never been anywhere for a bit event before (and it's not the best car being a 2000 GT).
I'm all about camber curve and wheel rate. I don't think the car needs to be any stiffer than what gives you a proper contact patch on the front tires. And in fact I don't want it to be super stiff as my tastes run to a more forgiving car over bumps. The trick with strut cars in general, and Mustangs in particular (and some VW's and Subaru's) is the camber curve sucks. You gain a lot of positive camber from roll. The answers are to run more negative camber, spring the car like a go-kart, or some combination in between. I've never been one to run a lot of negative camber for the reasons Mark mentioned. I don't like the feel or the lack of braking power. On the other hand I think a suspension should have some compliance for surfaces that are not smooth as glass and/or for rain.
I'm kind of in between, and what I do with one car isn't necessarily what I'd do to another. Different parts, suspension designs and so on effect the balance. I work a very different way (one that math folks hate). I look a lot at photo's, and do a lot of basic thinking about how the car feels and adjust based on what I see and feel. I'm to stupid to do math, and I also don't believe that formula's can make for a perfect car. If they did, nobody would test, and nobody would have to adjust their cars (from us all the way to Formula 1). The driver matters, his/her likes, dislikes, driving style... all of it play into what I do with the setup on any car, a customer's or my own.