With the Jaguar S-Type 4.0 you will soon be looking forward to doing at least ignition coils and sparkplugs to the tune of about $900. They fail frequently on those cars at that mileage. You may also be looking at replacing the timing chain tensioners for about $2300, as the 00 v8's still used the junk plastic equipment that's so problematic on the first gen. XJ8's.

The X-Type will almost certainly need ignition coils and sparkplugs as well, which will set you back $500 or so because 3 of the coils are under the intake manifold. If it's an automatic, you can expect to be putting in a transmission soon, they fail often on that car. Also, to replace the oil pan gasket (which leaks frequently) you'll be out about $800 because you must remove the transfer case to get at it. Other than that they seem to be a reliable car.

The S-Type 3.0 has the same ignition coil set-up and transmission issues as the X-Type, but they also seem to be a reliable car when those two problems are taken care of.

Both cars are built by Jaguar, but the X-Type shares a platform with the Europe-only Ford Mondeo. While the S-Type is based on the Lincoln platform and has the Ford-style fuel system, everything else is Jaguar. The 4.0 V8, by the way, is the same engine used in the XJ8 sedan, and not a Ford design at all (though perhaps used in some of their other cars, like the Lincoln V8).

My only advice is have all 3 cars thoroughly gone through and request any service receipts. The previous owners may all ready attended to the problem areas. So long as you know the cars are as maintenance-intensive as any other European luxury car and budget accordingly, you'll be OK.

Consider purchasing an 01 or newer XJ8 or XJR, too, as these are good cars and slightly more reliable than their X-Type and S-Type cousins.