Going on the GMC and Chevy websites and building your models will be a good start. It will allow you to see the base items and what added with different packages. Outside of the base models, everything else is personal preference and how many of the add ons you will want and utilize. For me I always want all the items available and will enjoy and utilize most of them which add value to ownership. Some will not want to pay extra for items in a package they wont use. That's where you can work with a dealer and order the things you want and not have the other things that are built into a package.