Cool, I'm glad this came up! I'm strictly a Bosch guy too!
Imagine my dismay when clipping in a new refill on the W124, a most annoying squeak made it's presence known which wasn't there before. I've machine polished the glass with Griot's Glass polish, then applied rain-x twice thinking that would get rid of the squeak - it didn't.
Is there a trick to inserting the blade properly? One condition I'm surprised of given my car's mileage is that the windshield is horribly pitted (I've seen better glass on cars with double my mileage). would this uneven surface cause the squeaking?
This is very annoying to say the least, and with the rainy-season coming (well, sometime anyway), I'd like to keep myself and my wife sane