The open air filter wont help very much, as the original air filter aren't even very restrictive. :p
Monday, i wanted to see how high rpm i could hit with my injection kit and at 9400 rpm and WOT, the Manifold Absolute Pressure-sensor read 973 hPa, which is very close to the normal pressure that day at 1055 hPa. This means that even at this high rpm, the original air filter will let alot of air through it and since there is very little chance that an open air filter will let the pressure in the manifold exeed normal pressure, it will only give a minor gain.
Of course, there is also the thought, that the engine might not be able to get rid of all the exhaust despite of my Leo Vince and that way give higher pressure, but an open filter wouldn't change this either.
