97 jetta glx bose premium sound system: aftermarket deck h..

as stated, i bought a 97 glx with the premium bose system in it. it has
the preinstalled amp in the trunk. i hooked up my aftermarket sony deck
with the harness. it powered up, played the music, but no noise came
out. someone told me if i attempt to bypass the amp or something, it
should work. i dont only want to change the deck, i have an aftermarket
amp and subs plus 6 speakers i want to change. i figure if i can change
the deck without rewiring the car, the speakers should be easy like the
previous jettas i have had (cut the clips off, take the four wires into
two and put the little clips on them to go onto the speakers
themselves.) is there some sort of aftermarket harness to plug into the
deck or amp in the trunk that will make it so i can do this all without
rewiring the car?