The 2004 S had 80,600 miles on it and was making some noise. The garage said it was either the super charger ($2800) or the water pump ($1300). Given it was also going to need front breaks in the next 6 months and a clutch in the next year or so, it seemed prudent to trade it in. Got $9250 for it and they discounted the 2009 S $750 so I got the bluebook $9998. But the selling point was 1.9% financing over 5 years.
The 2009 is slick - they made some improvements from '04 to '09.