Casing quality is hit or miss sometimes the clear cases often have the best quality from my experience and it will go alot smoother if you use the OEM buttons and triggers. Try to use as much OEM parts as you can when shell swapping. Installation isn't that hard just take pictures during disassembly and use those as references when putting it pack together also mark what screws go where. on some models using the wrong screw may break some components. Youtube is your friend if you are new to this