You asked a very wide ranging question. Many body and suspension parts are used across a wide number of years. The L-Jetronic fuel injection system is pretty much the same from model years 1981 - 1984.
The best way to know which year parts work with your car is to obtain the Porsche PET parts catalog. For each part number it shows the year range for the specific part number.
Rich
928 OC Membership Chairman
1993 928 GTS Cover Girl
1987 928 S4
1979 928 5-speed rescue
1979 928 Euro 5-liter track beast
Rich
Membership Chairman
Charter Member
1993 928 GTS Cover Girl
1987 928 S4
1979 928 5-speed rescue
1979 928 5-liter track beast