Time to open the proverbial "can of worms" here. I just purchased a new Hyundai Sonata (2012) with the 2.4 liter inline 4 cylinder motor. I live in Wisconsin and the motor is the standard ULEV 198 hp version. Right now the temperature is about -8F and the wind chill is around -20F, with a low tonight (actual temp) of about -14F. Several years ago i began using M1 in all of my vehicles and thanks to Pablo, Amsoil for 2 stroke and air compressor applications. I use M1 because it is relatively cheap ($23 for a 5 qt jug) and easily accessable at the local Wallyworld. It gives me the easy cold startups that I need in winter and slightly better gas mileage (0W-30 green in all GM vehicles) plus I have had no problems with extended drain intervals of 1 yr or 10k miles. My vehicles have over 200k. On to the Hyundai...the warranty calls for 4 month/ 3750 mile changes with 5W-20 SM GF-4. The dealer wants $30 for an oil change. I am sure it is a bulk 0W-20 conventional oil and a Hyundai filter. For under $40, I could purchase M1 0W-20 Green that meets or exceeds Hyundai specs, a Purolator Pure One filter and pay my GM mechanic $10 for the oil and lube service. The reason for the change to synthetics was cold weather performance and fuel savings. In fact, to plug Pablo, in winter here my air compressor would always trip the breaker with OEM compressor oil, but I have yet to trip the breaker during a cold winter startup while using the Amsoil compressor oil! In the vehicles, I was amazed at the difference in cold starts when I switched to synthetics. It sold me on their usage. Back to the Hyundai...today the Sonata, to my suprise, started and ran flawlessly in the cold with the factory oil. My wife will be driving this car. She generally puts about 7k per year on it and most of her trips are to work and back, a 3 mile trip each way. This means short trips and cold starts and runs are the most common drive. Summers can get hot, up to 95-100F during several days, with perhaps 15 total summer days around 90+ and 30-40 days right around 85F. The only dusty conditions are our gravel driveway. I will not be draining beyond 3,750 miles as I don't want any reason for them to void the warranty. What do you think? I can't say that I will use each of your recommendations, but I would be interested in hearing them and your reasoning. Thanks!