I've changed ours just recently from the summer 21's (AMG 43) to winter AEZ 20" winter and do not feel any difference....little noisier due to the tread but not strange for winter tires. I have experienced something like you discussed on a Porsche GT3 which has particularly light weight wheels. Aftermarket wheels looked good but were heavier and made the car feel different. Curious if you find out more.