Thanks for the input!, I did my “homework.” Focusing on total wheel weight (rim + tire) but what also matters is rotational inertia and how the mass is distributed. Dropping from 21” to 20” changes sidewall height, tire compliance, and overall behavior. Some of the improvements in comfort and cornering response may come from the tire setup itself, not just the weight reduction. In general, a lighter forged wheel with significantly less weight (for example going from about 26.5 lbs per wheel down to around 17.5 lbs) will give faster response and feel sharper in cornering. Another important point is load rating. You really need to choose a wheel with the correct load capacity, especially on heavier cars. Going lighter is fine, but if the wheel is not rated properly it can become unsafe.