I was thinking about switching the head unit in my 04 with some double din touch screen unit. I do have the Navi model and I was wonding if i would lose any of the current features. If you need anymore info please let me know

Thanks in advance

 

I don't know this could help you but change head unit is not easy since factory head unit has unique shape will required alots of modification(Somewhere in this forum has picture someone has been installed - which doesn't look good tho).
If you change head unit will lose display on the hvac module showing such disc info, track number, etc...

In my opinion you better consider CAR_PC than aftermarket head unit.