My set only consists of 3 live 8 ambient synth midi instrument tracks. After export, the synths sound like their parameters have changed.
Export options:

For the time being, I've found that the free vst plugin "HGS WAV Recorder" captures the audio from master nicely, although it's takes as long as the arrangement to create the wav file.
http://www.hgsounds.com/shop/vst-plugin ... vst-plugin
I am doing something wrong when I export?