Yep, pls don't use raindex on the windscreen. While raindex is a
very good product, u will still need to activate your wipers. But
if you have raindex on your windscreen, your wipers cannot work
properly and then u will have the juddering and screening
effect.
N raindex is so good that its effect will be there for a long long
time, so u will have to live with the wiper problems. 
