A question that is frequently raised in large enterprise deployments of Microsoft Dynamics CRM is can the local administrator and SQL SysAdmin permissions be removed from the installing user after the installation. The answer is “yes, but…”
Yes, you may remove these permissions after the installation is complete. The user who performed the installation will be able to log into CRM without having these permissions.
But…keep in mind that when it comes time to install an update rollup, to perform the database update, the user installing the update will need to have SysAdmin privileges in SQL Server.