The MotorStorm series was never officially released for PC and remains a PlayStation 3 exclusive. There is no official "PC download link" from Sony or authorized retailers like Steam or GOG.

If you’d like legal options, I can:

Recent updates to the RPCS3 emulator fixed long-standing issues like vehicle stuttering, allowing the games to run at 4K resolution on high-end hardware. Steam Deck Compatibility: The games are even playable on the Steam Deck

There is no magic .exe file. But that does not mean you cannot play.

Patches: Check the RPCS3 Wiki for game-specific patches that fix issues like split-screen shadows or stuttering.  MotorStorm Series Status on PC  Title  RPCS3 Status Key Highlights MotorStorm (2007)