What are pyrometers used for? Is it the kind of tool that is generally helpful, helpful only for people who track/autocross, or helpful only for tuners?

Also, can anyone make recommendations for particular pyrometers?

I Googled the word (define: pyrometer). Here's what I found:

A thermometer designed to measure high temperatures.

An electronic device used to measure tire temperatures.

Pyrometers are used in the racing world to measure the temperature at different points on a tire. By measuring the temperature (and therefore, the load exerted on that part of the tire surface), you can measure how effective your alignment is. Ideally, you'd want as much of the tire surface as possible being used equally.

Pyrometers can also be used to measure the temperature of other components, such as brakes, headers, etc.

most often in our world, it refers to a exhaust gas temperature gauge. but also as the other guys mentioned..it's kind of a generic term