Check if the one you have has the new body version, it should have 3 drain holes in the bottom. If it's not the new body, you can send it to shimano and the will replace the body plus add some more parts that goes with the new version. The new version has a better corrosion resistant coating. They will even clean the reel while they are at it, all for free.
I like the stock bearings in the CH50 MG better than the boca abec 7, it is quiet. The drags doesn't really stutter they are smooth but you can be improved by replacing them with carbontex. Other than that, you can pimp it by replacing the handle with carbon fiber but the stock reel is fun to use as it is. The CH50 MG is one of my favorite for topwater lures, it is smooth on the retrieve, cast light lures and best of all lite weight and saltwater approved.