Your batteries need to be in great shape. These engines take a lot of power when cranking in the cold with the glow plug heaters going. Are your batteries in GREAT SHAPE?
Dave
Get a good scanner. This is completely necessary if you own a 6.0. It will save you BIG BUCKS! I use an AutoEnginiuity.com on my laptop. Great tool.
Dave ;tu
Take it out for a drive and see how it is. Tranny shifts good? Steering feel good or sloppy? Brakes? How does it drive and handle? Any unusual noised? Does everything work? It looks good from what information you have provided.
Dave ;tu