My DMR-ES16's lid gets pretty hot for some reason, so I decided to install a fan, thinking it might be the reason the unit inserts or drops frames on it's own. I figure the chip's overheating. I used a Noctua NF-A4x10V PWM fan, though PWM isn't necessary. I took the 5V from the capacitator directly behind the optical out port. I wanted to drill and mount the fan to the inside of the case, but that would mean pulling the board to prevent any metal filings that could short things out later on. I decided to use hot glue instead. Easy enough.
The lid is far cooler now, and I don't see any drops or inserts by The ES16 itself, or at least few and far between. I'd get a least a few without it.
The only issue I've found... once the unit gets turned on, the fan will always be on, even after a power down. A minor inconvenience though. Unplug the unit when not in use.