I recently removed the Fishman sonitone pickup from my G45 Standard. I'm not here to suggest this is a good or bad thing just that if you do it, these are things you may consider. Procedure is pretty straight forward but I do have a few tips that may save you some trouble.
1. THIS IS THE MOST IMPORTANT PART: you will need a new saddle which is approximately 2.5mm taller than the old one in order to save the pickup if you want to re install it at some point. However, if you never intend on re installing the pickup you can reuse the old saddle if you cut the under saddle piezo element short enough to just act as a shim underneath the saddle. It's still best to have a new saddle made either way since you'll get even more volume and note separation that way.
2. There are small wire guides adhered to the underside of the guitars sound board, these will come off with some finesse, but may leave some residue. I wouldn't worry about the residue.
3. The control unit with the volume and tone control will come off easily if you gently pry on it.
4. The endpin jack can be annoying. You will need to find a nail or thin rod of some kind to put in the hole that is in the endpin jack while you loosen it with a wrench or pliers. Taking the jack out now is no problem, there are wires you can pull on. Since you will now have a 1/4" hole on the bottom of the guitar, you have two options to plug it, the best of which is to get an oversize endpin and simply glue it in like would be done from the factory. The other option, if you don't plan on re installing the pickup is to gut the end pin jack and reuse it. If you simply cut the wires and re install the jack you may notice a light rattle or buzz when playing or shaking the guitar, this is because the jack has parts that can rattle. In order to prevent this annoyance you will need to pry the actual electronics out of the jack and you will be left with a threaded barrel which you can simply reinstall as a normal endpin rattle free.
