Hey Frike,

At level 55 you become able to equip the Custom (crafted) or Raid Roach (uncrafted) which is the 'best' dexterity gear for your level. As for the older guides, they may be old but the game has been constant for the last two or three years now, so they still hold some valuable information in them that remains valuable and applicable to this day. I would recommend following those guides for now.