Assuming you already have the game, you can customize pretty much anything you use. That is if you have unlocked those options for each gun/vehicle. You can go into battlelog and choose your weapon setup in terms of scope, barrel type, laser/tac light bipod or foregrip. The same thing applies to your vehicle customizations. Armor you can choose your secondary weapon, Reactive armor, proximity scan and so forth. Choppers with your TV missile, zoom optics thermal ECM Flares. The loadout is the key to how you want to play. If you find the right setup things are far easier. Its worth the time to find out what you like using.
For example here is a sample of what I use.
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