Redline Light
 

I was curious on how to rig a shift light that would light up at specified rpm, cant always hear the buzzer. Dont really want a tach, mostly a subtle light in the corner of the dash, or something to that effect.

Well there are lots of shift lights out there. You just have to wire them in. (most of them come with instructions, but you will probably need a wiring diagram)

you are right... can hear the buzzer when with music on and on the track