any advantage in bigger valves?
 

lookin at installing larger valves into some sti ver 3 heads ported polished and matched ported with after market cams, when completed will run about 1.5 bar of boost, are there any positive gains by installing larger valves of 1mm or 2mm in diameter.............

I dont think you'd see the benefits only running 1.5 bar of boost, your just better off getting the porting and cams done, and leaving the valves as they are..

like joe mentioned, i wouldnt have thought larger valves would have a dramatic improvement with only 1.5bar, i guess a lot depends on the duration of the cam, the shorter the exhaust duration- the bigger the valve you want to evac those gases.