if theyre anything like the 124 theyre copied from if you lower them more than about 25mm it screws the steering geometry as the control arms will be pointing upwards instead of down/paralell. Thats said, if the sedan and wagon suspension is similar to the 124 coupe (does the wagon have leafs at the rear?) you can lower them alot if you dont care about the handling going to hell, I've seen one lowered 150mm from stock But I beleive there was a bit more than just changing springs, things like shortened panhard rods cutting bumpstops and maybe moving some of the mounting points for the rear suspension.