It's unclear whether you are having problems playing GT2, or you haven't even tried playing GT2... AFAIK, if you could get other games working in ePSXe, you won't have too much trouble getting GT2 to work either. If you could be more specific, that'll be great!
Try the old F4 key trick: press F4 once before loading or saving game on the memory card and once after the loading of saving operation.
What controller do you have? my memory card problems vanished the day I replaced my Microsoft Gamepad with a Playstation controller and an PSX to USB controller adapter.
I hope this helps
GT2 works perfectly for me now