If you'r in the market, then buy some proper ones,
Motorsport guys will use PIAA wipers, silicon based and last for years, no need for rainX ever again. They are twice the price of regular wipers mind but worth every penny.
Wet trackdays / wet motorways etc etc you literally don't need your wipers they are that good.
You can get them from Alyn at AS Performance I think and also camskill I believe .
http://www.piaa.com/siliconewiperblades