Get wipers with a BMW part number. There are a number of OE parts available. Bosch Aero has an OEM part number, so does Valero. Bosch Evolution is the generic version which fits many applications. The OEM wipers have the clip which only fits your wiper arms. All the others have a multi application clip which does not fit any particular application perfectly well. You can also get BMW wipers but they are pricey. I just purchased a set of Bosch Aeros from Turner Motorsports for $45. Much better than the Bosch Evolutions which were on the car when I bought it. Less chatter and no streaking. For about the same price, stay with OEM wipers. The savings is not worth the hassle of bad fitting wipers. I've learned over the years that wipers which don't fit well can be a safety hazard, this is why I buy only OEM.