Should I go back to Midtier?

Left my midtier firm because they didn't have the clients I wished to work on, for a big 4 firm.  I really loved the culture and people at the mid tier firm but just needed to leave to develop myself further.  The midtier firm has since asked me to come back as they have built out that industry.  I'm a S3 and believe they will try to treat me as a manager so I want to ask for a manager's salary.  Any advice?