I don't know about The life of Brian, but for "The last Temptation of Christ" there was bombing, not cars but a theater.
Now I actually agree that Christians are more tolerant about criticizing their religion than Muslims, I however think that:
1. it's more true within western Christians and not third world ones. It is actually because Western people are just more used to criticism of anything, have access to free press and have a longer habit of expressing one's view. If you go into a conservative christian neighborhood in a big african dictatorship, I am not sure you'll easily be able to project "The last temptation of Christ"
2. In "modern" and/secular "islamic" countries, protesting against the cartoons or Rushdie was less common/violent/popular than in "conservative" and/or poor ones. In Turkey and Tunisia for example many pepople just couldn't care less.