If we don’t use the kit accelerometer at all, are there I2C bus pullups (passive or active) inside the sidecar or we need to add them to our custom circuit?
The sidecar includes 3.16kOhm pullups to 5V. For future reference, they are on page 2 of the schematic at http://usfirst.org/roboticsprograms/frc/content.aspx?id=16337 -> http://usfirst.org/uploadedFiles/Community/FRC/Game_and_Season__Info/2010_Assets/DSC%20package.zip
Rock star.