First of all WOW haha what kind of horror fan didn't know texas chain saw was based on Ed gein?
The only 'real events' that the strangers was based on:
from wikipedia...
Inspiration
According to production notes, the film was inspired by an event from director Bryan Bertino's childhood: a stranger came to his home asking for someone who was not there, and Bertino later found out that empty homes in the neighborhood had been broken into that night. In interviews, Bertino stated he was "very impressed" with some of the theories circulating on the Internet about the "true events" the movie is allegedly based on, but said his main inspiration was Helter Skelter, a true crime book about the 1969 Manson family murders.
In another interview, Liv Tyler revealed that in Bertino's original script, "You saw a lot more of the strangers. It was much more of a Manson-esque experience."[3]
Google is
very useful. Try it sometime.
full wiki link
http://en.wikipedia.org/wiki/The_Strangers