suspension

Hello, I have a jaguar x type s 2.5. The plan is to keep the car for some time as it's got low mileage. I've put two new rear mufflers on it, will need a new center pipe soon. new plugs, filters, serviced once a year, MTEC disks and pads. There is minor cosmetic work but nothing seriously noticeable. I've had the suspension gone over and it's solid but the rear is starting to sound rough. But there's no play in the suspension so nothing can be diagnosed yet. I'm guessing the suspension is the sports version as it feels very rough and hard. Is there a softer alternative? The rear suspension looks simple to work on.