Yes, it can be done but no, it's not worth it IMO. It is extremely costly and labor intensive (from what I've observed from those who have added it on), requiring a rebuild of the entire dash to accommodate the idrive. You're better off buying some time of TomTom/Garmin. If that doesn't suffice, I would sell the car and buy one with idrive...
e92 335i: Current
e90 328i: Sold 12/7/2013