A&Q about 350Z
Q:
Are tachometers easy to install, or would I have to take my car to a dealer to get it installed?
A:
They're a pretty basic install. The hardest part is running the wire. What kind of ignition system do you have? If it uses a distributor you just connect the tach wire to the negative side of the ignition coil, if it's DIS you need to get a wiring diagram (from a haynes or chilton manual) to find which wire is the tach signal output.