I had a roadster several years ago, and the best thing I found was to run RainX on the windshield rather than a wiper. I was caught in one heck of a rainstorm north of Louisville one year, the kind of rain that had rodders stopped under overpasses. I did not have a wiper, and the RainX caused the water to bead and run off the windshield so I had no trouble seeing the road. Sometimes a wiper just makes it harder to see.