I was looking at the pic of your bike and it appears the bike still has original exhaust. You wanted advice so here it is: If the original exhaust is in good shape, guard it with your life. They are worth good money as most (original) GS owners ditched the stockers in favor of some 4 into 1 system. But unlike the Z1's or CB750 exhaust systems, no one makes a stock replacement/NOS exhaust for these bikes, and thus the originals are virtually non-existent, and are what really has the potential to make your bike worth some money. Not crazy money, but I had a guy on the GS Resources forum offer me close to a grand for my exhausts!