After CET-4 and CET-6, English still has a certain foundation. Generally speaking, you don't need to go to the basic class at this time, but choose the intensive class.

Is the TOEFL training basic class or intensive class better?

Personally, I suggest taking a test first. After all, there is still a big gap between CET-4 and TOEFL, which are essentially different types of questions. After the exam, you can know where you are at present, and then combine your target score to make a TOEFL preparation plan that suits you. The rest is TOEFL preparation.