Don't know about the extra bushing, but try some loctite or a lock washer on the bolts to keep them from backing out. Use the blue. (it's removable)
2008 ZO6 Corvette
MGW Short Throw Shifter, Hallteck killer Bee II CIA, 2” Primary StainlessWorks Long tube headers and X pipe, Billy Boat Fusion Exhaust, TR6 NGK plugs, LG G7-X4 cam, bronze guides, Titanium ultra-light retainers, Ferrea Stainless Steel Exhaust Valves, LG High lift valve springs, C5-R timing chain, .040 Decked heads, COMP Cams LS rocker arm trunnion kit, McLeod RXT Street clutch, McLeod flywheel, Hawk performance ceramic pads and a S&M Motorsports Dyno Tune.