Be careful. The camera lens is plastic and original Rain X is for glass only: https://www.rainx.com/faq/rainx-original-glass-treatment-safe-use-plastics-motorcycle-windshields-atvs/
There is no drain tube. That channel where all of the leaves collect provides the drain path for the cowl. Try pouring water into the hole on the passenger side of the windshield cowl and watch where the water exits. I did use a coat hanger and there were a lot of leaves in there.
We recently experience a lot of rain and noticed that the windshield cowl trim under the passenger side wiper was holding water. The little drain hole in the cowl was clogged. Here is how to unclog the drain: https://www.youtube.com/watch?v=G12FkJY9SYU
Interesting mechanical review of the CX-5: https://www.youtube.com/watch?v=nWNNE7oXnL4
Did you know that the transmission has an old fashioned dipstick?
I would suggest you stay with standard flooded battery. The CX-5 is not designed to optimally charge AGM. Plus, AGM batteries are more costly. Speaking of cost, the CX-5 can take either a group 35 or 26r battery. The Walmart Everstart 26r provides 540 CCA which is comparable to the OEM...
This is a very interesting comparison. I'm surprised by the results. For the 17s, did you use OEM size (225/65) tires? Did you calculate MPG or use MPG numbers from the dash display?