Here's a thread for alot of that info. And umm hope it helps.
Stillen HFC vs. BERK HFC
Has some posts on the FI ones as well. There are some other threads around as well even indicating that the Berks are in fact 300 cores instead of the 200's.
Then again, if you ever get into the situation and you need to worry about legality, go with the one w/ a CARB stamp.