Just after i started taking note of this board, i bought a psp slim from futureshop that came with patapon and headphones, if you do live near me the deal was on around black friday. It was the new box, no sticker with a letter. I don't know what firmware it was because I updated to 5.02 to take a look. My friend then modded the psp to 3.71 cfw - it worked. A note- the box the salesman gave to me was old, it had the texture of flattened carboard when it reflected light. I guess it was luck.
go for a slim