I have 1,200 miles on the truck and love it! 365 miles, I towed a 7x14 Utility Trailer, mostly at 70-75 mph and got 15mpg. I am averaging about 26mpg overall, minus the towing miles. My high was a trip from Colorado Springs to Denver Airport, about 90 miles.....37mpg! Anyway, here is my first question. The OCI is 10k miles unless the OLM says to change it earlier. Severe service is fewer miles. Anyway, I have always dumped the factory fill earlier in my new autos. I do not feel comfortable going 10k on the FF. What do you guys think about dumping at 5k miles? I have decided to go with Mobil1 ESP 5w30, as it has the lowest pour point, important for winters in Colorado. Second question.....is it just stupid to tune a new truck while under warranty? There are a couple of tunes out their that claim they are safe on the drive train, improve mileage and more importantly, boost the torque to over 500ftlbs. Would love to add a tune, but concerned.