Building a hierarchicaly ads system

Hey everyone. I have in mind building a hierarchicaly system using custom post types for car ads. I’m using simply theme (was something like ThirtyTwo ?) My question is: (i’m pretty new to wordpress, probably a couple of weeks experience )
Is a good practice representing the information about vehicle (for example :make,model,milage,body type, doors, etc.) with custom fields or it is better to use taxonomies for that purpose? It involves also building a refine search page for this and a public ‘post’ add? What is your sugestion? Thanks to everyone responding. (bow)