Well I have no idea if this has already been discovered or what....maybe I read the requirements for this hombrew wrong but I thought I saw that this is only intended to run on FW 1.5....I have a FW 2.00 psp and wanted to run P.M.G on GTA LCS and I've done it accidentally. here are the tools you'll need.

DevHook 0.44.0000 v2 Stripped Down Version by Chaos Zero ( i dont know where to find it anymore but I have a copy so if you want it maybe I can spare one)
Cheat Device
Pimp My Garage
Eloader 097(super Bock?)

Install all of the tools and load GTA(eloader too). The first time I tryed using PMG through eloader it didn't work...(kind of of pointless to say) So then I selected Devhook and confirmed everything and PMG played. I don't know how clear I am on this topic but if you need clearer instructions say so. Really crude waying of doing it but it works.