The X-Type is from a part of Jaguar's past that is currently in the doldrums. While it's certainly a better car than many gave it credit for, it's going to take time for people to view it as a modern classic. A lot of time, in fact - which means that if you're serious about keeping your investment in tip-top condition you're going to want to put some money aside for parts. A complete front and rear suspension refresh is a big job - can you isolate the parts that have failed and go after them one at a time? You can save money on these kinds of jobs by doing the work yourself, although I appreciate that may not be an option for you. This is the critical point in a car's life - where it's value is at the bottom of the curve, but servicing and maintenance costs are only going to go up. Time and money invested now will help this car through to classic status. But you'll need to be in it for the long game if you want to see any return.