While far from the quality of the first party shell, the aftermarket NES shell actually went through a revision and is much improved over the first one - you can differentiate the two if attempting to buy one by the rubber pads that cover the screws, the old version uses shiny silver while the new one uses matte grey. The new one fits better and is got better feeling plastics.
Thanks a lot! I actually find the GBA SP to be one of the most relaxing devices to open up and replace the shell, significantly easier than most handhelds - give it a try, you’ll have fun. I bought mine on AliExpress, super cheap, but do keep in mind that little trick I mentioned about the shiny versus matte grey rubber though because the old shells really do use some bad plastic. The new ones are much improved. The SNES one and the translucent ones are also using the same improved moulding and plastic.
Glad to hear it! I’ll make sure to keep an eye out. I might have to get started sooner than expected haha I’ll try to remember to post when it’s done :)