With some good double bush mechanics you can easily shoot at close range enemies without being spotted. There are no mods that I am aware of that change any mechanic of the game. Mods only work with information sent to your computer from the wot server. There is no way to change anything in the game, such as your ability to spot the enemy. That would be hacking the wot servers, which is not possible. Even the infamous warpack only relays information sent to your computer that is not normally visible, it is not changeing any rules or giving you any super abilities.