Well, bought my '05 in the summer of 2008 w/ 21,000 miles for $12,500 w/ extended warranty, which I thought was a great deal.

Issues I have experienced:

As you will learn (as I did immediately) plan on laboring over your headlamp lenses-they will etch and fog. It's not a matter of if, but when. Mine were replaced under warranty immediately following the purchase.

The rear hatch rattle (use search function, covered extensively)

Creaking/popping from rear quarter window trim (fixed under warranty)

Wheel clearcoat peel (personally, minor enough for me not to worry about)

As far as other problems, they are pretty evenly spread throughout the models, regardless of year. If there was a well known problem for the 2004 model year, more than likely a 2008 model would/could have the same problem. Overall, though, they are exellent cars. There are a number of active members on this forum who have near 100k on their cars and have had no major problems at all. Sounds like a good deal and I doubt you will be disappointed with your purchase.