Update: Replaced my battery succesfully last night. It took me about 30 min from starting to finish. On my particular battery, no registration is needed according to BMW service guys. Car feels great and my power issues are gone. I tested "REST" function and is working again along with rear defroster, blower fan for AC does not switch speeds like it used to either. All these thanks to the new battery. Hope this helps!
Easy thanks to the DIY and videos I found here. Total cost parts and my labor
$146.00 Cheers guys!