This is a main difference between the personality of good people and bad
  people.


Is the sentence comparing personality of good people and personality of bad people? or comparing personality of good people and bad people?

How to avoid ambiguity when using of with compound nouns?


Question: Mazda Air Mass Meter - where can I buy one?
Answer: Like this one? Not sure if your models match up to American ones, but this site might help. Hopefully they ship internationally.