Technical Stereo Upgrade?!

[coghlac3]

Have a stilo active sound and luv it. Wanna put a dvd player in it. i'm thinkin that a boot changer would be the tidiest way..... I don't wanna disturb the in dash player. Want to keep all the controls the same so dont have to disturb anything. Does the stereo have an aux input? Basically all i need to know is the best way to use my current stereo's speakers for an additional source, ie dvd changer. Then the monitors and power cn be run straight to the boot. Am I even making sense? is this at all possible?