First off, let me say that this may be common sense to some. BUT, I didn't know it would require so much customization of the cab on my end. Also, there are probably a few different ways to do it. This is the way that worked best for me, and now I LOVE my PRRI. It sounds huge! The blue speaker is everything you'd expect too. Chimey clean and rich, full overdrive. Let me know if this helps! STEP ONE: Get all your supplies together.MojoTone baffle, Speaker, Amp, Tools (Drill, File, Pliers) STEP TWO: Remove Baffle by unscrewing the screws holding it in. It is best to remove the tubes furthest to the right and left to allow room for the drill and prevent later damage. You'll also notice in this picture the two bottom sections of wood used to screw in the cabinet. The one on the right will need to be removed. STEP THREE: Screw in the new speaker to the new baffle and see if it fits, just to make sure. If it is the MojoTone baffle, you'll notice it does NOT fit. It is too tall to fit with one of the bottom braces, and slightly too wide on one side since the baffle is offset. STEP FOUR: Remove bottom brace. You can do this any way you like. The wood is not very strong so I just drilled into it and the kind of pulled it out. I'm sure there is a better way though. Luckily, once you pull it out, it comes out cleanly and smoothly, except for the little nails that I just pulled out with pliers. STEP FIVE: Once the bottom brace is removed, see if the speaker fits. I am assuming, like mine, it will not. Then mark off on the side where it is the speaker is coming in contact with the cab. It should only be about a 1"-1.5" spot. I filed a little too widely, but it doesn't matter. Really just the one area is enough to make it a perfectly snug fit. STEP SIX: Once you've filed it down enough for the speaker to be a perfect fit, you need to put pilot holes in the baffle, which comes without them. Once you do that, you should be able to drill screws into the baffle relatively easily. The baffle should fit snugly, without any rattle. Hope this helps! Best of luck!