If you want to get almost "very high" visuals in DX9 I'd go with Gaco's 1.01 config here:
The only things that are missing are the higher quality DoF, motion blur and shadows.
You can also add a few draw distance tweaks as reported in this thread (they do cost another 6-8 frames):
And at last you can give sgio2 configs a try:
Most configs do try add "DX10" visuals and they cost performance so if you are not happy with how they perform at all settings on "high", I'd rather try the "performance configs" instead of the configs that improve the visuals.