If you love Forza Horizon for the fast-paced, arcade action and car crashes (like the Hot Wheels DLCs), Burnout Legends is a must-play. It is not open-world, but the sense of speed, destruction, and soundtrack is unmatched on the PSP.
It does not exist and never will. Continuing to search puts your device at risk from fake download links on forums like RomsMania or CoolROM . Instead: Forza Horizon Iso Ppsspp