Doesn't it come with several front sights of different heights in the box like the P99 and PPQ series?
Good point - try some different ammo first.Check power factor of that crap ammo you got on sale!
At a recent match a chap was shooting white box crap and when it was put through the Crono it wasn't even making minimum power factor.
Pony up for some Sig or Hornady top-shelf stuff and see if it doesen't shoot a good bit higher!!!
THEN worry about the bloody sights!!!