Waldo, I just sold my 98 XK8 coupe at the beginning of June. The 97-01 model years had trouble with the nickasil cylinder lining and the cam chain tensioners. High sulfur gas corodes the nickasil and the tensioners were made of plastic. If the nickasil is bad, there is a severe loss of compression. If the tensioners have not been changed to the newer, metal ones, the cam chain will jump a tooth or two and ruin the engine. The water pumps have a plastic impeler that breaks over time with age. All of these things can be fixed, but at expensive Jaguar costs (special tools required). The convertible tops are quite well known for bursting their hydraulic lines and creating quite a big mess. The self-dimming rear view mirror is known to leak and ruin the wood on the console.
Enough said.
I had my car for 11 years with 42 K on the clock and did not have any major problems, but I also did not have a convertible or have the tensioners replaced. I suggest you check the jag-lovers website. Any other questions, let me know. The 02 model year fixed many of these problems.