I would suggest you contact Sandi Jerome - President of Sandi Jerome Computer Consulting (
sandi@crsauto.com), Paul MacDonald of Tri-Mac Computer Consulting (
mail@paulmac.com), or the Paul Gillrie Institute (ask for David at
dave@houssian.com). All three of these firms specialize in assisting dealers when evaluting and purchasing a new DMS. All three are very impartial and will help you to understand what each vendor brings to the table, what systems are the best match for your business, and what you should expect to pay for the system.
Hopes this helps.