The mansion is the center of your hood. Destroying it will mean a win for the enemies. So always secure them and guard them with the best available Mobs and Bosses. Mansion will also let you store a good amount of Cash and Product. Upgrading your mansion will always reward you with opportunities to expand your businesses and other buildings and may also let you train your Crew further. Also, it is at Mansion, where you can train and upgrade your Bosses, Including Marco and Jane.