Are you sure it is the setup that needs work and not the driver? I don't mean anything negative with that remark, it is just that it takes quite a bit of concentration and practice to get the best speed out of any setup.
If you are certain that it is the setup, perhaps post what the car is doing that is in need of improvement and we can suggest setup changes that will help improve it. I say this because anyone's setup that gets them the fast times may not work for you as your driving style and line are almost certainly different from anyone else's.
