ES is simply a trim level it may have some odd reasoning behind it but overall it simply explains what equipment and features this model has vs another model
if you want a complete shop manual look to Helms for that, if you want a basic manual that gives you a pretty good idea go to a local parts store and see what they have to offer there, if you want a user manual as in the book that came with the car try ebay, if you are looking to download any of these welcome to the internet
no it doesnt make a difference the D16W4 will be the same regardless whether or not its in a wagon