............depends on the head unit. IF it has a built in amp with front and rear speaker outputs, you are golden. Running new speaker wire from the head unit to your speakers (totally recommended on cars this old) is a snap.
Current : 2013 Mini Countryman JCW, 2007 Z4M Roadster
Past: '88 E30 M3, '69 BMW 2002 Ti, 2000 328i, Audi A6 TT, BMW X5 3.0i , Audi A4, Mini Cooper Clubman S 1.8T