I assume that not Chad stole the guitar, but Tommy. Eye rings compare Troy and the MC. He then gave it to Quinn, who in turn gave it to Chad. Chad gives it to Sage and the MC has to interact with Sage to get his guitar back. This creates a relationship of Sage and the MC, which then later creates the possibility of Sage and Chad breaking up. Tommy also has the MC straight to go after Sage. Now nothing stands in the way of the party plans of Quinn and Tommy, because the tradition party's of Hot's and Alpha's will no longer take place, since the president of the HOT's and the Alpha's have separated. Sage wasn't cool with drugs, but Rusty doesn't care. Rusty just doesn't pay for it. But that's what Quinn is expanding for.