For sure, 20's are a BIG wheel for a Protege. I wouldn't go bigger than 18. My first choice would be to stick with a light weight 16" wheel. My second choice would be a 3rd generation Miata 17" wheel. The Protege is VERY sensitive to wheel weight, and a light weight 16 with a 205/50-16 tire is the best set up. Second choice would be Miata 17 with a 205/45-17 tire.