My 2016 GS is so sweet, my buddy wants to try out the GS space. He's looking at a 2005 GS with 86K miles. Says the guy has all service records. What can he expect to be going bad or wearing out on this bike? What should he be inspecting for? What service should have been done by now by the seller, if he was keeping up on things? Asking price is $4500. Advice please! Thanks.