Getting new wheels(20") will mess up abs sensor?

I have 16" rims on my 2001 Yukon right now and plan on buying and putting on 20" rims tomorrow by myself. Good or bad Idea? I need to save money I know it'll mess up my speedometer (how much would that cost) but I have my speed on my gps. Would it effect my abs and any other important info I should know will be appreciated, thanks.