I run mine in the surf almost every ride. I have the brain exposed as well as everything else.
The only things that can go wrong are the earth connections, shorts on the plugs/caps and shorts between the coils and mounting plate.
These problems can be overcome by using di-electric grease in the plug boots and making sure the leads aren't sitting against metal surfaces. Mount the brain on a perspex or fibreglass board so the coils can't arc against it, and make sure all your connections (especially the grounds) are good and solid.
The only other thing remaining is the trigger air gap and the front cover area, which is no different than stock.
Set it up properly and scoff at people without total loss!