Guys and Girls,
Brand new to the forum and Pioneer in general so hoping someone might have some light to shed.
I have a 2006 Cadillac CTS-V (Bose/Navi) and an aftermarket Terk XMD1000 XM receiver/tuner.
I'm looking to:
a) overhaul the entire Navi unit with an Avic unit (recommendations would be good)
need a breakdown of what's needed for this so as to retain most or all driver info functions (the car has onstar, steering wheel controls, park assist/voice + regular DIC functions i.e. warnings/odometer/battery etc etc).
c) if possible I wouldn't mind retaining my existing Terk XM setup as the dealer is paying for the subscription 
Any advice would be appreciated.
Avic unit needs to accommodate in order of priority: Navigation, Ipod/Aux, XM, bluetooth, HD storage preferred. Doesn't have to be latest and greatest...
Again, thanks in advance.