The NeoSynergy DMS
NeoSynergy, Inc. | Revolutionary Web Applications That Connect Auto Buyers and Dealers Online. does not require a CRM system. It has one single database able to support thousands of concurrent users. It has CRM functionality everywhere and available to the users where the user is performing an interaction that touches the customer whether transactional or proactive.
So that is one approach, but it is new.
Another (for those not prepared to change their DMS to get it)... The other is to not prescribe technology solutions (like DMS integration to CRM functionality + systems) without defining how such integration would be used.
I used to be somewhat famous in teaching CRM to dealerships and implemented one of the most documented successes of it. We did have integration with the DMS (all transactional data in the CRM system, able to desk a deal in the DMS, able to push the deal to F&I in the DMS, used the CRM system to follow up all prospects, service and parts customers) including scheduling phone calls & emails with dynamic next steps scheduled according to prior activity outcome.
More importantly, dealership net profits increased 30-40% per year for the 3 years I lead this effort. Technology is no silver bullet without the people + processes to make it effective. So integration between DMS and CRM is not going to change things one iota without defining why it matters & how the process will be more effectively delivered because of it.