Actually I just installed one one my 97 hatch. Its pretty easy. just cut the wire from the back of the tach. then I think for auto-meter they have 3 wires? the red(positive) black (negative\ground) tachometer wire(dunno what color).
the black ground can pretty much be screwed into anywhere where there is metal from the frame of the car. The positive needs to only be energized while the car is in the "on" position. For this you tap into the ignition wire. Follow it from your ignition (where you put the key in)one of those wires will be a pretty think yellow wire. thats the wire you need to tap into. for the dash lighting wire, I just tapped it into the same wire as the positive wire, so now my tach is lit up when the engine is on, whether or not my dash lights are on.

I think there are alot of do it yourselfs online. just type it in in google.