I got my 4612 model back in 2006. They sure have gotten pricey over the years.
If towing, driving in hilly areas, or added help for a conversion van, then these are a must to have. Sure, they look too simple and are you really going to see a benefit; that was my thought at first. However, these perform just as well as the documentation says they do. If getting another Ram Van, yes, I would spend the 300-400 for another set. Hope this answers your questions.