Digital verification teams increasingly rely on large constrained–random regressions to achieve coverage closure and find bugs early. While robust orchestration platforms ensure repeatability and visibility, static test selection often leads to redundancy and slow progress on rare or unhit coverage targets. This thesis presents a comparative analysis of using Synopsys VC Execution Manager (ExecMan) alone versus using ExecMan together with the VSO.ai Regression Optimizer plugin. Grounded in official user guides and common industrial practice, we define a simple framework to compare workflows, coverage trajectories, stimulus diversity, and resource efficiency. ExecMan alone provides strong execution management, coverage merging, and reporting, but leaves test selection to manual curation or broad, static lists.