I am picking up a 06 coupe next week, it originally came with the 17" tires, but the dealer is swapping the 17's for 18's. Will the speedo need to be recalibrated with the wheel change? If so does the dealer perform this service?

 

No calibration needed.

 

no calibration because if dealers is not dumb he will change with wheel/tire setup that have the same outside diameter of your old wheel setup. It's the tire profile (thickness) that compensate for direfence between 17 and 18 inches wheels. With the 18 you will have less rubber "cushion" on the wheel.