2002 330CI ride height?

I can tell my suspension needs a refresh and I would like to try and do it myself this Winter when the car is in storage.



I bought it two years ago and it was well maintained. A few people say it looks like it has been lowered an Inch or two.



Question one: How can I tell if it has been lowered?



Question two: If it has, how can I replace the parts and maintain the same height?