2009 S5 Price increase = +3%
Not sure if you got a copy of Viper's complete 2009 Audi Order Guide (thanks vip), in that guide it lists the 2009 MSRP for the Audi R8!
The R8 went from a base price (6-sp manual) of $109,000 to $112,500 which is an increase of 3.2%
While the R8 is not the S5, the R8 is even more rare and could easily have handled a larger price increase.
Therefore, I'm betting the base MSRP price of the S5 comes in at +3% also... like my dealer told me. That's $1500 increase on the 6-sp manual.
Hope this helps.