So in order the difficulty goes like this?

  1. Quant 2. Derivatives 3. FSA …the rest?

I would have originally agreed with you (With the exception of derivatives - not there yet!), until I watched the Heatherington lecture from Stalla. Now I’m pretty comfortable with quant and would not consider it a high difficulty section going forward. ***Disclaimer: I do have a few econometrics classes under my belt. Good luck!

^isn’t mathematical statistics better and more relevant than econometrics?

IMO, yes. Straight stats is more relevent to the CFAI material than econometrics, but they’re highly integrated. As well, econometric methedology (Learn to read the output, not a full comprehension of the process) is similar to the CFAI approach.