Its possible to adjust the bloom effect by editing the last few lines in General10.fxh and then recompiling the DX10 shaders.
The lines in question are
static const float fHdrSpecularScale = 1.11;
static const float fHdrEmissiveScale = 6.0;
static const float fHdrCopyScale = 4.25;
static const float fHdrModAlphaScale = 3.92;
fHdrSpecularScale is the one that changes how much metallic objects shine.
Default Bloom (1.11)
Bloom on fHdrSpecularScale = 0.0f
Bloom on fHdrSpecularScale = 100.0f
Lights are more affected by float fHdrModAlphaScale
Bloom on float fHdrModAlphaScale = 14.0;