Well for really good overclocking, then you'd look into water cooled systems, as adding more fans will only do so much. Don't mess with your PCI-E bus settings, if you're going to overclock stick to FSB/voltage increases. As always be careful and do some research on overclocking your particular CPU without damaging it, ie not increasing core voltage too much.

A 200-210MHz increase in FSB isn't a bad oc, with over 100MHz gained in core clock. Apart from that, you might want to try tightening your RAM timings.