UKPassats

Can someone tell me if it is possible to use the existing headunit gamma tape unit and cdplayer below connected up to an external amp is there a lead i can get to do this i dont fancy taking out my radio as it sounds ok and would take the look of the dash which i like. but i am wanting to run a small sub. Not shy about working on I.C.E as my last 2 cars where done by me but this is my first vw passat b5.5 and dont want to change headunit. I already have an amp and sub and 2x head units from last cars dont fancy going and buyin a blaupunkt pnp amp.

Thanks Guys
Andy