Vmoded my Gigabyte 8800GTS yesterday; I used 500ohm and 50kohm VRs:
http://ceemic.pri.ee/hardware/8800gts/mod1.jpg
http://ceemic.pri.ee/hardware/8800gts/mod2.jpg
http://ceemic.pri.ee/hardware/8800gts/mod3.jpg
http://ceemic.pri.ee/hardware/8800gts/mod4.jpg
Glue-gun-boss

Def voltages rised to:
Vgpu 1,167/1,218 -> 1,193/1,239
Vmem 2,02V -> 2,04V