is there a coil pack or tach lead wire that can be used as a shift light trigger ? OH btw this is on a 2009 G8 GT

No. If you want a shift trigger light you'll need an aftermarket tach with a shift light built in. Then you set the light at any RPM you want. You could probably get a 'mini' tach to fit somewhere. Check these: http://www.speedhut.com/gauge/GR2-TACH-03/1/Tachometer-Gauge-10K-RPM-mini-Shift-light

and whats going to trigger the add on tach?

Any coil pack that's convenient. Older cars had a single coil or distributor wire you could tap, that isn't the case anymore. Most people just tap the number one coil ( purple ) wire for the tach._____________ If you really just want a shift light, I take back what i said about having to install a tach. TORQ makes a standalone shift light. Try this:______ http://www.torqspeedlab.com/store/pontiac-g8/g8-gauges/g8-shift-lights/g8-raptor-shift-light.html.__________ Looks real easy to install.

Hey would this be the same for a G8 v6?