Is the teaching about Christ in you in Romans commonly taught in churches?
No. The Romans teaching under discussion is described as not normally taught; it opened a listener's eyes to things she had never heard before. It is presented as deeper material the Christian community needs today, calling believers to get into the doctrines God has revealed and to believe and trust them.
Les explains that he teaches the Word in a way ordinary people can understand, and he notes a listener had heard how this teaching in Romans opened her eyes to things she had never heard before. From this he concludes they are teaching things not normally taught, getting a little deeper, and that this is what the Christian community needs today. He stresses getting into the doctrines God has revealed, hanging on to them, believing them, and trusting them. The transcript does not explicitly use the phrase "Christ in you"; it refers generally to "this teaching in Romans."