I did a search on egt and I still couldn't answer my question. What does an egt do that an a/f does not do?

A friend of mine gave me a a/f to install on my n/t talon. So would it be better to install an egt instead of the a/f.

You really don't need either...

Both gauges tell you whether you're running lean or rich, but the EGT does a MUCH better job at doing so. The A/F just looks pretty.

What Darko means is that you don't need to worry about your fuel mixure if you're not running boost. The stock fuel system can take care of the normally aspirated engine just fine. People who run a lot of boost want to keep an eye out and make sure their engine gets enough fuel for the amount of air the turbo is pumping.
In your case either a/f or egt will be just as rice . Why don't you give it to me?