If your ecu box develops a water ingress situation (was a concern of mine when I had a location adjacent to the rear wheel before), an idea I added to my front mount alternator was a small, remote located computer fan (they run 12vdc) feeding a 1″ ID hose that develops very slight but positive pressure into a cover fiting over its front. This works really well in keeping it cool, as well no rain or spray gets into the workings, even tho its right behind the front wheel.