Thanks to all on the battery information. As promised my update: I now have my IPhone 3G and IPOD working through the XLR's audio and OnStar system. I installed the CoStar Tech BlueSTAR PnP GM Class II kit. Took only about 10 minutes once I figured out which pair of connectors to use from the VCIM, white was the OnStar and black were the NAVI system (thankfully I bought the Service Manuals). Just unplugged the OnStar from VCIM and plugged into BlueSTAR. Done deal, use the OnStar buttons to answer calls, mutes radio, and sounds great. Second installation was a SoundGate GMPD2 IPOD interface. Found XM connector at upper portion of passenger seat, in the trunk area (didn't have XM unit installed). Used connectors provided, plugged it in and ran IPOD connector into storage area between seats. Connected IPOD and use XM features on radio screen to operate. Can select playlist and scroll through songs from screen. Total time, including searching and research in service manuals was about 40 minutes. Now need to take it for a ride, interior is much roomier than trunk! Thanks again for all the help with my questions.