Now that I've compared a number of cars, I've come to the conclusion that the S-Type suspension is rather firm, but very precise. This is somewhat different than some reviews I've seen where they say the S-Type suspension is soft. Compared to the Audi A6, the S-Type is a lot firmer but is much more agile and grippier. The Audi is smoother and softer, but not as performance biased as the Jaguar. The Ford Taurus I used to own was much softer also which is due to it being a family car vs a sports sedan.

The closest car I've had to the Jaguar is oddly enough a 1971 240Z. It was a true sports car with the expected stiff suspension and quick, precise steering and handling.

Mike

 

I thought suspension was good but spongy on my STR.
Once I found out that ALL the bushings and wishbones needed replacing,the suspension is night and day different. Solid and responsive without the stiffness that can get old on long drives.
I recommend that all you S type guys keep an eye on those bushings, they go away even on low mileage cars.I had one leak a clear odorless liquid from the inner bushing,thought it was a tranny line leak. When they put it on the hoist, he showed me the stains of liquid on the wishbones.
Keep an eye out for that staining.

 

I also find the S-Type suspension to be firm yet comfortable, and very responsive. Mike, I had a 1974 Datsun 260Z and agree with you that the Z and the S-Type handle quite similarly. I had my Z from December 1974 until December 1987, the longest I've ever kept a vehicle in my life. I still miss that Z and would love to have it back in pristine condition. With that long hood and low seats, I could fold my 6-foot-7 frame into that car very comfortably and drive all day and all night. It was the first new car I ever had and will always be emblazoned fondly into my memory banks....

 

The S type R's suspension surprised me when I first got it. Very firm for an 'old man car', and you can really feel it on rough roads. I like it though when I happen to be doing 120 through a bend. :-D