I would not use the regular stuff. They do make a rain-ex for plastic but I have been reluctant to even try that on my new poly-carb enclosure...
RainX is alcohol based. It will fog Eisenglass. Not sure on EZ2CY, but a carnuba based wax should repel water without attacking plastic.
Haven't tried collonite, but Hardline's UV protectant might be another option... YF member review... http://www.yachtforums.com/threads/...aner-polish-for-eisenglass.25184/#post-222885 Manufacturer's page... https://www.hardlineproducts.com/product/rx-uv-protectant-cleaner-polish/
I found this on Amazon searching Hardlines products. It says it the "New" polish. https://www.amazon.com/Hardline-Pro...-1&keywords=rx+uv+protectant+cleaner+&+polish
Try some Mequiar's quick wax detailer. Just too easy to use... a polymer not a wax...sheds water well. Can use it on most everything that shines outside and inside.
Just tried the Rain-X for plastic for the first time on our newest 37 express I delivered to the vineyard last week with an acrylic enclosure (Everclear) and it worked just as well as it does on my trucks windshield. I didn't see any fogging or negative effects. I'd previously tried Plexus 210 and Collinite but neither worked 1/10 as well as the Rain-X did.
Clean the ez2cy with either aquatech or IMAR strataglass cleaner......then wax with either Collinite insulator wax (recommended by EZ2CY) or the IMAR strataglass polish if the EZ2CY has fine scratches....the insulator wax works REALLY well and is the best for EZ2CY usually.
With the insulator wax, rub it on there a little to work it in, let it dry completely and rub off with a microfiber. It goes on and off pretty easy and a little bit goes a long way.