Compare two strings and get the difference

You need to make sure the larger set is on the left hand side of the Except (not sure if there is a pure Linq way to achieve that):

    static void Main(string[] args)
    {
        string s1 = "i have a car a car";
        string s2 = "i have a new car bmw";

        List<string> diff;
        IEnumerable<string> set1 = s1.Split(' ').Distinct();
        IEnumerable<string> set2 = s2.Split(' ').Distinct();

        if (set2.Count() > set1.Count())
        {
            diff = set2.Except(set1).ToList();
        }
        else
        {
            diff = set1.Except(set2).ToList();
        }
    }