It is but you need to have access to a PSP fat running 1.50 or custom firmware to make the Pandora battery pack / Universal Downgrader to downgrade the Slim PSP
Yes it is, (I have a 3.60 M33) It is actually very easy to downgrade (once you have a Pandora's Battery and a Magic MS). You just have to do a few things to convert the PB to work on the slim and then its super easy.
If you get a slim and need any help feel free to PM me.
no, a spare battery is not needed. you can use one battery, convert it to pandora's battery, use it on the psp patient, and convert it back to normal.
but it's recommended to get a second battery and memory stick so you can keep it as the universal unbricker v3. because if you full brick, you have no other way to get it back unless you have those two items.
if you use the universal unbricker v3, it will put any psp directly to 3.71 m33-2, or official 3.71 when needed.
i have used it on my own psp slim, and it works with no problems.
I made a guide on how I installed 3.60 M33 on my slim. I found that this was the easiest method and only took me about 5 minutes to get the Pandora's Battery to work on my slim.
