First i can hear it because it's in the fanless part of my case, and overall my system produces very little noise. Most ppl say they cannot hear fans that i can hear 2 rooms across, or HDDs that produce a distinct whistle, or even pumps

Comparatively, this pump is noisier than Eheims. Like i said nothing disturbing, if you've got a fanned case anyway you won't hear anything. Its real strength is the price...
About pressure, i'm nout sure about the impeller housing, but porting the inlets may be beneficial, one has to have a spare inlet cap though, just in case