I put in an AeroForce Interceptor multi-function gauge - connects to OBDII port and provides LED indicators for RPM threshold you program - see pics on post #1 this thread -
http://www.camaro5.com/forums/showthread.php?t=47343 . Still seeking a single gauge A-Pillar pod (the Fesler offering didn't fit well so returned it).
Its useful when running tapshift to remind you to "tap" when eg 2500rpm is exceeded though I've found I have a better feel of the rpms now with use of the tapshift.