Impact of changing v_st, eff and κ_eff, the two free parameters of the CR model, on the stellar-to-halo mass relation at z = 0. We varied κ_eff at fixed v_st, eff (left panels), and vice versa (right panels). The black curve shows the relation from the realization with the fiducial TNG model (no CRs), and the various colored curves are simulations with CRs. The bottom panels show the ratio of the various CR cases to the TNG model, where the dashed black (gray) horizontal lines show values of one (0.25 and 0.1). In most models with CRs, the stellar mass growth is significantly suppressed. Varying κ_eff at fixed v_st, eff has a minimal impact, while larger values of v_st, eff at fixed κ_eff lead to higher stellar masses, closer to TNG values. Throughout the paper, we adopt values of 100 km s⁻¹ (5 × 10²⁸ cm² s⁻¹) v_st, eff (κ_eff) as our fiducial set of transport parameters (red curve, labeled TNG-CR). For this case, we also contrast against a simulation without SNe/SMBH feedback (NF; dashed orange curve). Finally, for comparison in subsequent plots, we also consider a weaker model (the blue curve, labeled TNG-Weak CR).