I run 18" and 20" Budnik's, and if the car is a show car, weekend warrior kind of build, they look great. No reason not to go with the 20" then. If you road race your car, and weight and handling are a BIG concern, then I wouldn't go this route. I personally like the looks, and since WHEELS are my business, I wanted a nice looking big wheel combination. My suggestion is to take a good long look at what YOU expect out to the car.
Call me at Budnik if you want to talk more about it.
"The Custom Wheel Experts"