
Modding cards tends to yield only tiny benefits if any benefits at all. Gainward were among the top manus for the GF3 cards and used very capable cooling so I'd leave it alone, your money and time would be better spent selling up and putting the extra towards a GF4TI4200 which would improve 3D, image quality, AA, TVout/VIVO, dual display, o/c very well and take much better advanatge from the faster CPUs which are dropping in price all the time. Of course GF3TI200 @ 230/490 is capable of playing ALL current games well, if you want more selling up and upgrading is the wisest course of action.
GF3TI200=175/400 GF3=200/460 GF3TI500=240/500

Considering the price diffs there were between these cards you should be very happy with 230/490 esp since it seems it isn't even the Golden Sample version. You're so close to GF3TI500 perf I wouldn't bother getting more, the chances are heat is not the limiting factor so even if the new cooler was better it is unlikely to give much if anything mroe.