  We study the constraints on the mass-splitting of the first two generations
of left-handed squarks obtained from Delta M_K, epsilon_K and D mixing. The
different contributions from gluino, neutralino and chargino diagrams are
examined in detail, concluding that it is not justified to neglect electroweak
gaugino diagrams if the squark mass matrices contain flavor non-diagonal LL
elements. We find that the constraints on the mass-splitting are very strong
for light gluino masses. However, if the gluino is heavier than the squarks the
constraints on the mass-splitting are much weaker. There are even large regions
in parameter space where the different NP contributions cancel each other,
leaving the mass-splitting nearly unconstrained.
