Most parts are the same. The cradle, brake calipers, front motor mount bracket and suspension parts are different on 88's. When I replaced all the radiator hoses on my formula I found that the crossover pipe and the hose that connects it to the coolant pipe on the drivers side were different too.
Edit to add the body panels are all the same. Interior colors vary from year to year too.
[This message has been edited by DLCLK87GT (edited 02-03-2014).]