Hi Mike and the team,
I share the exact same problems and am running the same gear; 7950 GT, Athlon x64.
Here is an old Nvidia PDF.
It quotes: GeForce*7800*GTX/GT:*Transparency*antialiasing*does*not*work*with*G rand*Theft*
Auto*San*Andreas.***
The driver does not apply Transparency antialiasing to triangles that are alpha-blended.
Applications with alpha blending do not benefit from Transparency antialiasing.
Would this help at all with some kind of troubleshoot?
Love the game, despite not being able to see through grass, and appreciate that you visibly put time and effort into frontline customer support.
Thanks.