Change management and Implementation of SAP CRM 
(see whitepaper)
One of the most challenging areas is with the  implementation of CRM solutions, as this touches areas of an organization which have a strong autonomous culture; such as the sales and marketing functions. It will require them to work closer together and to build common objectives and approaches. 

If market segmentation is introduced and customer visits are monitored then guaranteed the the sales reps will feel as if they are loosing their "freedom" and their entrepreneurial "flair". The resistance to change can be extremely high . 

It's therefore important to focus on education of the teams on the benefits and advantages. You need to answer the question "what's in it for me?"  Ensure to tailor the  benefit for each separate team, as each area of the organization will have different motivators - normally the impact on their bonus 
 - showing them that their sales will increase and hence the bonus -or they save hours of paperwork in their home office!  Otherwise they will blame the CRM for not meet their targets (regardless of whether it's true or not they will still use this as an excuse) and the the sales director's will be at war with the project team!  

It’s at that point that executives must determine how best to make employees understand these changes, and incentivize them to do it, and do it gladly. 
Ensure to give sales directors and sales managers a very attractive bonus on successful completion of the solution otherwise other activities will take priority

Consider implementing a change management program which begins with a communication plan and an approach to respond to those most resisting change. Staging your communications in a logical order will help prepare staff and slowly erode change resistance. Plan to over communicate and implement activities to spot those individuals that will resist. These are the individuals to address in one on one sessions and seek additional assistance from their peers and supervisors.

As user adoption is a frequently cited contributing factor to failed CRM implementations, a change management program can literally make the difference between success or failure