Basically you want a 4.2 engine, so be looking at model years 2003 and up.

 

There are lots things to check out. There are some characteristic problems, common to specific years. Most of the early year issues were corrected by model year 2003. The general list of things to look out for when buying a used XK8 has been dicussed at great length a number of times. Search here and Roadfly for them. It makes a big difference whether you can do your own mechancial work or not. If not, understand Jag dealers are very expensive, so find an independent shop BEFORE you buy and have him check out the car. Also consider an aftermarket warranty... also discussed at length on these forums.

 

I think the summertime is the best time to buy the coupe. Most jag shoppers are looking for the verts in such nice weather. Opposite holds true for convertible shopping in the winter. I agree with Gordo on the above recommendation. Small issues on the 03s and up too, but nothing like what the earlier models have seen. If you browse the xk8/xkr forums you will see where most of the mechanical issues arise from, at least from our members here. Not alot as you will see for the 03s +. Try to get an xkr with a Jaguar Select Edition warranty (jags version of an extended warranty), if you do, you'll be set until early 2010 for the major stuff. Definately good piece of mind to have, and worth the extra value of the car.