I use air and Im fine and I assure you I push one of the highest performing systems on CF. Its all about proper case size, layout of the hardware and air flow direction.
Heat causes the density of the circuits to decrease due to expansion, therefore data and electrical current are depleted by not having a solid transfer line. Sort of taking a solid cup of ice and crushing the ice inside...conductivity is substantially decreased.
As for overclocking the CPU, you can overclock it all you want, but if your peripherals / pci / pci-e cards and rails can't handle the increased volume then you have gained nothing and created a bottleneck.
Same thing with your monitor...if your monitor cannot handle the increase in performance that your Graphics card can produce, you gain nothing at all....matter of fact, you could shorten the lifetime of your monitor regardless of what type it is.
A performance system needs to be performance from start to finish, not just one component or two.