kiwijunglist: passive colled psu will not provide airflow out of the case therefore case may run hotter if it isn't adequately ventilated.
I would also consider psu with large 12-14cm slow moving fan, it's it large and slow it will be quiet and you will also need less case fans going.
Yeah, I believe that's why the Zalman PSU has it's heatsink outside of the case. Definitely would be a problem if it was stored in the usual AV cabinet under a TV eh