Well if it were my truck, and still within the warranty period I wouldn't extend the drain intervals beyond that which is recommended in your owners manual. You could use Mobil1, Amsoil or Redline and extend your drains to 10,000 miles (perhaps even more)and most likely never have a problem. However, if you did have a problem with the engine, you can bet your last dollar the dealer will make mention of the OCI and type of oil used (API certified or not). Trust me on that. Would they prevail in denying your warranty claim? Probably not but why risk the hassle?
If you want to use one of the quality synths and feel good knowing they are keeping everything squeaky clean go right ahead and do so but keep the OCI in line with your owners guide. It sort of stinks draining that pricey stuff so soon though so I would just use a quality Dino or blend (Chevron/Havoline, Schaeffers Supreme, Castrol GTX, Pennzoil) and pocket the savings.
My .02
Mikep