navigation is not a must i think but is packaged with technology package which also included parking camera, new navigation is linked with an app on iphone, you can send saved maps from google maps to your car, it is very convenient, it will look odd to put a garmin unit on 55K car so suggestion get technology package, HUD is also not a must, i would rather go with M package. i had premium sound in my last 328i, it think it is lot better than the regular sound, if you listen to talk radio you can skip it, HD radio is very good sound as compared to E90, my point is premium sound in this vehicle should be standard at this price point. Lane departure is very good safety feature (i agree not must).
2013 X3 XDrive28i Sapphire Black Premium Package, Technology Pack, CWP, SAT Radio, BMP APPS.
2013 328xi Mineral Gray, Moonroof, CWP