I had a back-lit (AGS-101) Game Boy Advance SP that had a broken hinge for a year or so. I picked it up cheap on eBay with the intent on fixing it. I came across a vendor on Amazon that was selling full shell replacements for the SP and jumped on it. I always liked the black SP but the back-lit models did not come in this color. It was a perfect opportunity to accomplish this with a new shell.
As you can tell from the photos below, this thing was in bad shape and needed some TLC.
After about an hour or so I ended up with a working black back-lit SP.
I ended up not using the screen protector that came with the Amazon one since the original actually looked fantastic after a good cleaning. I also changed most of the triwing screws to standard screws.