Yes. Based on your question, the one who needs to know that you are not someone to mess with, or rather the one who needs to stop messing with you, is you!
In other words, what you are really looking for is mastery, not power or control.
T'ai Chi Ch'uan goes very well with SFQ and is a great martial art (you do have to search to find a school that actually practices the martial aspects of T'ai Chi Ch'uan, but it is well worth it).
The other suggestion I would make, is Aikido. This martial art comes from the same place of love as SFQ does.
These would help you a lot, I think.
Hope that helps.
