The tuner is a car enthusiast (or as some call him a car guy)that will modify their car to achieve maximum
performance.
There many non car people that considur tuners as "maniacs" beacause they love going fast and having loud cars,but this is not the case for a lot of them.Most people take their racecar to a track and race it there
The chosen cars are usually
performance models of normal cars(hatchbacks,sedans,wagons,coupes etc).
Cars used for this are either jdm cars or eurocars,but the modern
muscle cars are taking off in the tuner world
There are also the ones that only modify their cars on the outiside only.If done right with quality parts then they became stancers but if they use low quality parts off ebay and wish for example and they make the car generally worse they are considered ricers