97-2006, are the springs/struts the same through all the years, if not what is compatible with a 2003 xk8 (not with that fancy sport set up).

 

There are differences in years and also in convertibles vs. coupes. Best way to be sure is to use your VIN number when locating these parts.

If you use any of the non-dealer suppliers, there is an array of options that will likely require a call to a human to get straight.

The spring rates on the coils are very important as the wrong set will have you ending up with a lowered front end.