I am currently under contract for a SFR. The property is leased for the next 11 months and under current property management. I plan to continue with PM but want to evaluate the existing group. Does anybody have experience with this? Main thing I am curious about is when is the appropriate time to reach out to manager to begin building that relationship and evaluate them.

I don't think it would hurt to reach out now while you are under contract. That way, you are ready to go, whether it is them or someone else, once you close on the house.