Its not worth it. You can simply overclock your card to GTX speeds (depends on card). That card was fast enough, with full pipeline and same memory as the GTX (but with tighter timings), pretty much the same like Maserati MC12 and Ferrari Enzo

Flashing a graphics card is easier if something goes wrong, you still can recover it by using a PCI gfx card and flash to original BIOS (I've tried it). Do it on your risk though