You can set the driver's side door to refuse to lock, so it is impossible to lock your keys in the car; pushing down the button doesn't lock the door, you have to use the in car systems or the button on the key.
To unlock the rear hatch while the car is running, you must not only click the button, but must also engage the parking brake.
To disable the Traction Control (at least most of the way) press the TC button. To disable (at least most of the way) Stability Control, press and hold the TC button. To disable both of those and the Antilock Brake System, pull the ABS fuse (this really disables the first two, not just most of the way)
(1.4T specific tip) The onboard computer is equipped to handle any mix of ethanol and gasoline, because that was in the original design, however the final decision was to release the car as a gasoline (and up to 10% ethanol) vehicle. This means though that you can convert to flexfuel by simply adding an ethanol sensor, which plugs into an existing port on the ECU and installing a flexfuel specific tune... at least two of our vendors are offering such tunes, Trifecta and Vermont Tuning.
Nothing you can do to your car will have much effect on power with the stock tune, because the stock tune is designed to reduce power to meet the original specs of the car. Any tune that overcomes this artificial limit will allow slightly more power from the 1.8 and significantly more power from the 1.4T, and will also allow you to benefit from any mods you want to do. I believe every tune people have mentioned on this forum has this effect.
The stock tires are awful in cold conditions, one of the best handling mods you can get are replacement tires, either "all seasons" or, if you have significant cold weather, actual "winter" tires. The stock tires are not awful in hot weather, although some have reported getting better performance from dedicated summer tires, if you don't want to spend that much, getting just winters and using the stock hankooks during the summer isn't a bad option.
The fuel tank holds 12.2 gallons. The gauge shows empty at about 2.2 gallons. Each bar is roughly 1 gallon, and when you go from one bar to no bars, you have about 2 gallons left; if you know you're getting 40 mpg then you know you still have about 80 miles to stop for gas. However (at least on the 1.4T) when you do run out of gas, you are out... not like my old F150 where I can probably coax another 5 sputtering miles out of a "dry" tank. Here, out of gas means out of gas. Also, your "miles to empty" won't show you how many miles you have left, when your gauge says you are empty, instead of helpfully informing you that really you have 60 miles, or 20 miles, or 5 miles, to go, it just says LO.