I downloaded and installed Redux v.1.4 on the most recent version of GTA 5 exactly following the steps on their website. Upon starting the game I can see the Redux intro video and symbol on the lower left hand corner. Billboards/Brands are also replaced. However, everything else is in the original version. (cars, physics, graphics, loading screen etc.)
I would be grateful for any help on how to implement the other changes as well. I've tried installing multiple times.