Lingenfelter has a high performance 9.5 inch differential for the G8. It's made for racers who want more options and more strength than the OE unit delivers.
How about gearsets up to 5.88? Improbable-some would say impossible-with the factory unit. It is a piece of cake with this new differential.
Same for gearsets in the 2 series, allowing you and your G8 to take on terminal velocity, maybe even over 200 mph
Check out the photo describing the unit's main features.
G8 differential specs