@robev Depends what you mean by "part of the Torah". Does the Talmud anywhere say that a specific chilazon is required? (I am aware of the general statement in the Tosefta.)
By the way, is Kazi your family name? I ask because I see it is an Hungarian family name (and I'm guessing you're Hungarian from the "bácsi") -- but I'm more familiar with a given name preceding "bácsi".
@Alex who said anything about required? Whether or not other sources are valid, there still is one that is discussed in a notable way and can be referenced unambiguously.
If I recall correctly, I remember someone saying in a shiur a long time ago that a dishonest person cannot do teshuvah. Is there any source for this claim?