Have you even done a blind test between a passive k402 system and k402 system utilizing DSP?
While i understand your feelings having been there myself, you're leaving a lot on the table.
As far as I know, the only passive I'm aware of that can be purchased for a Faital driver ( HF200) is from Crites...
Good luck with your quest!
( Just a FYI, those radian drivers you're using are quite good, i know many k402 owners who use them w/wo BE and are pleased with them.)
Erik