I just recently purchased a new 2006 Sport edition 4wd 4runner 2 days ago. The 4runner has the JBL synthesis upgrade stereo which is the 6 CD/Mp3/wma changer w/ 10 JBL speakers. My question is I haggled with the dealership and they agreed to install an OEM factory navigation that they will install in 3 days. Will I still be able to use my 6disc mp3 changer that is installed presently or will Toyota remove it completely? Also should I expect any problems with the Navigation unit with the JBL 10 speaker system? Thanks in advance for helping out a newbie.