Just installed the Weathertechs yesterday. The research I did suggests the WT's plastic is more robust than OEM. The front deflectors simply slide up into the weatherstripping (make sure you follow instructions re: front lower portion), the rear do too in addition to having adhesive strips. WT says to keep windows up for 12 hours, most likely to get the deflectors and window seals comfy with each other. My glass hit the deflectors several times before they finally seated. So far so good, haven't lowered the glass yet (raining here). Only complaint: Upside down WT logo on driver's side triggering my OCD.