bose stereo question

im having trouble finding info on the bose system in my 2000 gtp. i was thinking about adding a amp/ sub and possably a head unit, but i remember reading that the bose system is not easily compatable with non bose equiptment. i dont want to replace the whole system because it does sound pretty good as is and i dont use that car enough to justify spending 2 grand on a new system.is there anyway i can install a powered sub to the existing system? i assume i could get an aftermarket head unit with sub outputs, but dont know if the bose setup works with an aftermarket head unit. all i use is the ipod, and these fm transmitters are really getting annoying. anyone that s been through this or can help id appreciate it. i figuredid post here since its a factory setup, but if the admins think this should be in the car audio section feel free to move it. thanks all for the help

im pretty sure that best buy sells an interface for the bose GTP's that allow you to swap out the factory head unit for an aftermarket one. Do yourself a favor when buying one.... Get one that has red illumination.

Maybe what I would do for the sub installation is to buy an amp with high level inputs or else get one of those line converters that splice into the feed for your rear speakers and converts the signal to RCA's. I know that both of these ways are going to be inferior sound quality to other setups, but I myself couldnt justify spending a ton of money for a bose interface (lucily I dont have bose) nor could I seemyself swapping out the factory headunit for one of the crappy aftermarket ones. (most of them look so ugly nowadays if you ask me, and the ones that dont, dont have red illumination.)

Seems to me I priced out that bose interface from best buy once and at the time was over 100.00.