I've had cars track right because of the heavily rutted and slightly sloped (for drainage) roads in my area. Tracking left is odd.
The STi is the straightest tracking car I've ever owned. I can release the pressure of my hands on the wheel (essentially hands-off) on the highway or on side roads and I usually don't have to correct the steering even slightly for 20 seconds. This was a total surprise to me since I figured that the sticky Potenzas would follow every cigarette butt tossed out of the car in front of me.
My dealer has a full alignment done as part of the PDI. I'd recommend one in your case.
The speedo issue is covered in other threads, and others have documented the same error. I don't have a GPS with which to calculate the speedo error on mine, but I will try to do it in the near future.