I live here in seattle where it rains more often than not in the winter,
I have noticed no weakness with the monowiper although I do use rainx,
I like just the way the water just blows off as if it were the canopy of an F16.
I agree that it would more than likely be a great idea to be sure the mechanism is proper lubed and clean if you belive it is inadaquate or too slow,
mine works great. I'd recommend only buying OEM wiper replacements, belive it's bosch brand.
Cheers!!!

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1991 300e 255K (14.62mpg)
1979 Corvette L82 (sold)
2000 Custom Harley Sporty 1200
(Ride Hard or Stay Home!!!).
1973 Dodge Charger 440 (sold)