I have no regrets getting the MSport and Dynamic Handling. They are worth every single penny for the driving experience.
I know it's hard to find a Dynamic Handling car out there because they are usually only on custom orders. But if you can find one, please try and compare the driving difference to a non-DH vehicle. It's definitely not subtle.
The navigation system itself is integrated nicely in to the car. Yes you could get a Garmin. But I personally find the larger LCD screen a nice touch from the small one. IMO, the small one looks like crap and looks weird in the center console. The larger screen fills out the area nicely.