Re: Tire size/Speedometer accuracy
Everyone should have a smart phone and Torque. I can display the GPS (actual) speed right next to the OBD (car calculated) speed. No guessing or even thought required.
Just been playing with an 8" Windows tab and my smart phone. Both can connect with Bluetooth and music sounds the same that way or using the AUX input.
Clarion M303 is neat just need to do something about all of the unused wires in back.