Not quite as simple as that. If you currently have the centre console with a cubby hole under the arm rest (that has a chilled air vent), and you want to swap the armrest outer for one that holds a CD changer, MDI shelf, IPod adaptor etc., then you do need to swap your current air ducting.
It joins to the front section around the area of the cup holders, and has a small branch that goes up to the cubby hole vent. Its this branch that gets in the way of the MDI shelf / CD changer. VW do a similar duct piece especially for the MDI/CD Changer version (without the small branch) that also routes slightly differently in the centre console to avoid MDI / changer version.hardware that would be fitted. It's only a few pounds, but is an absolute b*tch to fit. However if you want working air vents at the back, swapping this piece is the only solution.
If you currently have the low line centre console fitted (I.e. Without the armrest,) then the front piece of the air ducting will also be missing. It can be retro fitted fairly easily, but involves completely removing the centre console. Behind the ashtray, the main dash air vent ducts will be blanked off where they would go backwards to the armrest. These blanks can be removed and the 2 section ducting for the rear vents fitted ( rear piece as type explained above Depends on if you are fitting the cubby hole armrest or the MDI / CD changer unit instead).
Hope this helps.
Andrew
Andrew