Sure, you CAN use any oil you want, but the question should be SHOULD you? The answer to that is use EXACTLY what your owners manual lists.
0w-30 or 5w-30 may use 0w-40 synthetic motor oil
use BMW Synthetic 5W-30 oil or Mobil 1 Synthetic 0w-40 oil
The lower the first number the better (for cold). If your vehicle uses 5W-30 oil normally you could go to 0W-30 for the winter months. Typically the oil cap on your car will say on it what oil to use. Make sure you use an oil with the same second number as recommended but the first number can always be a lower number. Some cars run with 5W-30 and some with 5W-20. The one with 5W-20 can also use 0W-20. For cold weather it is best to use the "0W" 20 or 30 because of the cold starts. The 0W helps the oil flow a little easier at cold start ups. Also using a full synthetic is very helpful too in cold weather starts. So, go with a full synthetic "0W" oil in winter. Both Mobil1 and Valvoline make good full synthetinc 0W-30 and 0W- 20. I use those brands in my vehicles in the winter.
0w 30
Why would you want to use an oil other than what Toyota specifies for the car? I presume your car use 0W-20. I don't know how close the tolerances are in your engine, but SAE 30 will probably be sufficiently thin at operating temperatures to get into the clearances required for full film lubrication. It looks like you have two years left on the warranty and four years on the power train warranty. If you put 0W-30 in you car and have a warranty claim,Toyota will have good grounds to deny your claim.
Mobile 1 0w 30
5w-30 is recommended but you can use 0w-30 as well. You can also use synthetic oil if you wish but it is not needed.
You should use a synthetic Mobile One 0W-30 or 10W-30.
any 0w-40w, use 5w-30 and your safe
Mobil 1 full Synthetic 0W-30 or 0W-40.
You can use the factory oil change package that is about $30 or you can use a 0W-40 oil mobile one makes it and there are a few others.
AMSOIL 0w-30 with an AMSOIL Duel-Remote By-Pass Filter.