I have a 2011 Mustang GT with just about everything Whiteline Suspension has to offer, K-springs, 20 inch F-14. The car still feels a bit squishy around hard corners and I was told today that I should consider a set of new struts. Koni is what was suggested but wanted to know what everyone else thought.
I'm running Koni Yellows with the same springs. (Actually, UPR Pro Series springs, which are made by Eibach
to the same specs as Eibach Pro Kit springs. This is the same thing FRPP does with their K-springs) Anyway, they work well together.
I'm personally holding off on struts and going for a back end suspension swap of:
LCA relocation brackets
adjustable panhard bar and rod
that'll give the improvement in cornering without destroying your ride comfort.
I have to suggest the opposite. If you are primary concerned with ride comfort, I'd go for the struts and shocks and leave the control arms and panhard bar alone.
That said, I have fully upgraded suspension on my S197 (guess which brand) and I'm running Koni Yellows. I took a customer for a ride in the car today and he was blown away with the ride quality. He said it felt like stock suspension to him, but the car corners like it's on rails. My point is this- usually people who complain about NVH complain about the control arms, not the dampeners. I personally feel that the ride comfort is still good with fully upgraded suspension.