The glasses are for the 3D vision that Nvida has, Which the 430GT might have problems keeping the Frame rate up for 3D Vision.
But the Physx doesn't help performance, its a visual quality setting, enabling it will make things such as a flag in the wind more fluid moving. But Physx is only used in a hand full of games, here is a list of games the Physx works in http://developer.nvidia.com/physx-games
Physx does not work in every game such as Battlefield 3, it indeed has physics, but it is done on the CPU which is called Havoc, It does the physics on the CPU no matter what GPU you own.
To enable the Physx I can't remember off hand on my old 9800gt. Its in the advanced view in Nvida Control Panel. I run an ATI 5850 so I forget where the setting is.