Running the MM passively cooled only?

[suicideneil]

Well, the fan only kicks in at ~150°F on newer versions ( anything newer than v2 I think- I love my v1 & it's constant fan ), so unless you are really hammering it the fan doesn't tend to kick in very often, and only for a minute or so based on what I've seen.

A larger heatsink on the FETs would be a good start, just carefully peel off the stock one & maybe use thermal adhesive to put the new one on, rather than thermal sticky pads ( better contact & heat transfer ). A heat-sink case may not do much as there are few components on the underside of the esc's PCB that generate much heat, and due to height differences you'd have to use thermal pads again..