gbax is doing the voltmod to (most of) the guaranted gp's they are selling.
http://console-fix.co.uk/ is offering teh volt mod for 10£, i think gbax is also using their service for the mod.
when you buy a blu from liksang you will maybe get 133mhz maybe more, arround 50% of blu's should go to 166mhz, and dont forget taxes.
when you get a 166mhz one from gbax its 166mhz, maybe 172, but not 180.
when you get a 180mhz one it is testet to 180, but not higher, can even be 200mhz with luck.