IMO the JTS springs are too soft on their own. You get too much body roll. you loose all your static camber, and thanks to the strut front end's poor dynamic control of roll centres, that goes haywire as well. So in long sweepers you get a car that by mid corner behaves totally differently than it did when you turned in. And you still have the most important part of the corner to go - the exit... where you start to really try to get on the power, transferring more weight to the rear and compounding the problem! Turn 2 at QR is nasty in my coupe - doesn't help that there is a massive bump right on the apex.

Its not such a problem on short, low speed corners as the shock helps initially, the loads generated aren't as great, and you can set the car up in the first half of the corner to overcome the problems. Can't do that in long sweepers, you're stuck with what your setup gives you by mid corner.