Going looking at an 1990 e30 touring tomorrow, anything particular to look out for ? main places where they will rust ?

Only seen the car from the outside so far and from there only rust i seen was on the sun roof, bringing trolley jacks with me to get a proper look underneath as well.

NCT is out since 2008 but from what i have been told the asking price is very cheap so i know its going to need bit of work most likely but my main concern will be the rust.