I'd recommend using this process to prep the window first:
https://www.youtube.com/watch?v=i-Ai4y1WoOo
Then go with Aquapel.
Lightyears better than the Rain-X which behaves like the monsanto of window treatments, requiring needless additional applications, and their stupid washer fluid. And if ya don't then they punish you with wiper noise.
Try the Aquapel once, you'll never go back! I did use Rain x for 15 years and wish I could have all my time/frustration/effort wasted back.
Also, if any of you use claybars on the windshield, ditch ALL the junk claybars!! You have TWO options:
1) Mequiars professional mild or aggressive
2) 3m correct it, beware, you want the stuff made in Japan.
All the other claybars belong in the trash can and are a waste of time (yes, groits, cg, all of the yellow clays = junk = really just scams, and they should be cutting everyone refund checks for wasting your time requiring you to go over the same section 2-4x, whereas the 3m = one shot.