if you really want to install it on the back all neat and tidy like u see on twitter, then desolder all that solder and remove the capacitor. you can put the cap back later if you want. there are lots of good guides (just try google images) for installing on the back. it looks great when done well 🙂 you can also follow the megaamp v2 instructions for installing the audio part.
nothing wrong with installing it on the top. once its installed you will never see it again anyway !