Hi, I have a Canadian E550 2011 (W212) with COMAND NTG4.0 and Factory Rear view cam. I was wondering if I can upgrade my NTG4.0 COMAND to NTG4.5, or NTG4.7 (3rd Gen 4.5). If so, is it a plug&play install? Meaning can I just purchase an NTG4.5 from eBay and install it in lieu of the 4.0? If not, can the modifs be done be me or are they "hardcore"? Also, if I upgrade to COMAND NTG4.5, will I have the active guide lines in the rear view camera? if not, is it possible to enable these somehow? Thanks.