Cheatah. That link and that part are for 97-03 GP's for the passenger side. I believe the 04+ already came with that passenger cowl installed. Now for the drivers side, I don't think their ever was a cowl over the wiper motor, not that I'm aware of anyway. Maybe someone else can chime in. The water that's leaking in, is probably coming from a worn windshield seal.
Now, are you sure it's water and not coolant? Could be coolant. I know that sometimes you have to look really hard to notice that sheen of green in the liquid. If it's coolant, could be a leaking heater core, or heater core hoses are leaking at the fire wall, in the engine bay, and the liquid is finding its way inside. Had that happen to me! Heater core hoses were dry rotted at the ends where they connect to the heater core fittings right at the firewall.
