Travelling along the A13 today and a massively loud high pitched impact sound almost made me soil my pants. Looked around in a slight panic (without swerving from lane to lane, happily) and there is a big ol' impact site and crack about an inch from the top nearside corner of the screen. After going around a few corners quite enthusiastically, it the crack grew quite a bit more. It's not a repair job, so a replacement is needed. Which service is the best? The car (W210) has rain sensing wipers, are all the windscreen services able to deal with this? Anything I need to watch out for? BTW, didn't find a suitable technical forum to post this in, please move if it needs moving. Thanks in advance.