first off, the cars. Carmax will offer more than most dealers but at what cost? you will spend your days selling through mismatched paint, cars that have to be jump started, and "valuemax" cars that should've seen a junk yard crusher. Want a question answeres? better go "partner" with someone else. Remember the scene from office space where everyone asks the dude about his TPS reports? thats carmax.
skip being a sales consultant and apply for sales manager. promotions are not based on actual impact within the company. As a consultant who wants to become a manager, you have to achieve a club level status (directors or presidents club) this takes a lot of time and a lot of cars to be sold. Then you are given projects handed down by sales managers who have little input but will take credit after completion for the task and also add that they "developed you"
Do yourself a favor, apply for manager and you will be trained by a consultant who wants to be a manager for a month. You will ultimately skip years of ups and downs as a consultant, be paid more than the average consultant with big bonus opportunities