I have a double din bose head unit, was wondering if i could keep that in there but attach another cd unit, which will attach to the bose hu and somehow play into the bose head unit...which will output to the speakers...is that possible?

 

Not sure why you would want to do this, but it can be done (ie CD changer) via tape adapter or fm modulation. Both options however will have a much poorer sound than a cd.

 

there's a standalone cd player mad eby sony for bose, i want to attach it to my double din. Using cords.