Best of all would be if carmakers would set up their ECU's with lots of electronic options that you could jack into with any laptop or PDA/smartphone and set on your own- without proprietary software. Or with proprietary, but free software.
I had a third party VAG tool for my previous Audi that would let you plug into the OBDII port and allow you to change settings (I could set the car to autolock at 5 mph, allow car to unlock all doors or just the driver door, allow all windows to come up or down by holding down the lock or unlock button), so it was quite useful.
Unfortunately, nothing like that for the Mazda. I don't know if it's because no third party vendors have bothered to make something like that, or if the ECU just doesn't contain the software to change all that stuff in the first place. Ah well...