I got an xmod car as an birthday present a few years back. They didnt give me an screwdriver though.
I bought some screwdriver made for these small things (size #0, and size #1), and it worked, kind of. They wouldnt budge, so the harder I tried, the more it got stripped (first PSP), on the second, I tried again, and it started to strip too since the screws were stuck. Then I learned a trick from a guy, where I heat up the tip of the screwdriver, then unscrew while the screwdriver was hot (loosens up the plastic making it easier to unscrew), but what the guy didnt tell me was that I am not suppose to reuse the screws that were heated up, so I stripped it screwing the PSP back together.