Hi,
yes, you would sample position and rotation every nth time and save it in an array. you'll also like need to save a timestamp with each sample so that you know when to show a particular sample ( or loop through the array with a timed loop system).
don't use FsmArray for this, it will be not optimal, prefer using ArrayMaker which uses lists that can grow without affecting perfs. FsmArray uses built in arrays which are best to use with a fixed size, and at least not a ever growing list during the game loop.
http://answers.unity3d.com/questions/227657/record-ghost.htmlalso, you'll need an interpolation system to move smoothly the car between each sample, that's likely more tricky then recording actually.
maybe, you could search for splines and path systems on the asset store and ask them if they have such solution already built int, you might find something cool.
Bye,
Jean