Instrumentation panel cluster, I believe.
(2009.5 version is required) for engineering mode GPH and MPG-instant. Us older folks have no option to upgrade.
2009.1 ZEPCOM MGM G8 GT
Kooks LT's, SOLO HFC & Mach Unbalanced with J-pipes, SLP Tips.
Livernois tune, VCM, FE3's, full Holden blue gauges conversion, iphone on display. Daily Driver FTW
The ZEPCOM G8 was SOLO's test mule
Bought 3/30/2009, retired 7/18/2017 at 136k miles, still strong. Been a great ride, she will be missed!