I recently purchased a 06 GS300 without the Navi system. Now after about a month of driving the car, I really regret the decision not getting one with the Navi option. anyone here can give some inputs on which option to go with, getting an OEM navi unit or simply go to Costco and get a Garmin GPS?? After reading some of the posts here about hacking the navi & DVD system... I truely think getting one with the Navi option is the best choice, but I guess its too late for me. anyone install an after market in-dash Navi in a GS before?? Thanks in advance