"Similar vehicles" is one of the best functions of a good CRM system. Here are a couple example of how you can use this excellent functionality.
Trying to do this manually would take forever and be nearly impossible. So it takes smart software to compare the year, make, model, bodystyle, price, mileage, engine, and all sorts of other factors to evaluate which vehicles are the closest matches.
Initial auto responders. Rarely do customers buy the car the inquired upon. So why not give them some more options right up front? More options to contact you and come to do your dealership?
In this example, the first vehicle is what they inquired upon, and the next 4 are similar vehicles. This same technology can be used to supply similar vehicles to a new car lead, or similar new cars on a pre-owned lead.
Unsold follow up - Weeks later the car they were interested is now gone. Why not send them some similar vehicles that you now have available?