Have they told you when it will be ready to pick up?
Here's the best information I can find on the Nav.
2012 Subaru WRX and STI research page: WRX, Premium, Limited, and STI, STI Limited, 4 door sedan, 5 door hatchback packages
The 6.1" Nav system is all new for the 2012 WRX and STI.
The 2011 nav system was 7" for the WRX and STI.
The 2012 Legacy nav system is 8".
Maybe it's a smaller version of the Lagacy's setup, maybe it's an updated version of the Kenwood 7", maybe it's all new.
Sorry I couldn't be more help.