Just to share my settings/performance:
- October unit (Asic 1 = 4 VRM, other 3 are 8 VRM but only 4 active)
- Firmware 0.99-tune
- Clocksetting on 231, no other firmware changes.
- Harware mod: Lowered the Asicboard-fans (more airflow over the board), added 2 fans at the outlet (so now push + pull) and slightly lowered fan speed to reduce the noise (80%).

Images
Status page --> 676 GH/s / 9131 WU
Advanced page --> 2.5V SPI and 256kHz frequency, slightly modded volts (higher, as required for the increased clock), not completely fine-tuned.
CGminer --> Error rate used to be 3%@560GH/s, since I lowered the volts a bit after the initial increase this increased to just below 4%. Fine with me as it lowered the temps 5-10 degrees an decreased power to 'around' 40 W per DC instead of closer to 50 W.
Pool stat  --> 650ghs average
Power consumption in bertmod used to be 453 W, now it is 651 W (43% increase in consumption for 18/19% performance increase). With voltage finetuning the power consumption should be able to come down a bit, now it is all pretty much on the safe side (safe as in: higher voltage as required to avoid that cores get shut down).