1. You probably mean "ripped off".
2. Yes, it's correct, although I would prefer "entered" to "joined" as the verb. Capitalization of "Championship" is OK if it refers to a previous mention of a proper noun, for example, "World Robot Championship". However, if that name is actually the "WR Cup" we also see mentioned, then "championship" should be lower case, referring to the common noun.
3. Incorrect. "Whose" here would refer to the WRC, which is presumably parentless.