I woun't even speak to the quality as I've never seen nor used the Bigwater kits. What I can say is that I doubt very serioulsy a single fan radiator tucked into a drive bay could dissipate enough heat to make it much better (if at all) than a good and cheaper air solution.
I'm not a fan of the Swiftech compact kits unless you are space limited in your case - which the Armor is not.
The Swiftech H20-220 is a good introductory kit that you could build on. Also, Petra's Tech Shops has "kits" it's put together form individual parts if you're afraid you'll over look something.
Bigwater kits are seriously flawed by their poor pumps. Their 'high flow 350 L/hr' pump doesn't perform nearly as well as the Liang/Swiftech branded MCP655 (1200 L/hr) plus you have a small radiator to cool a single CPU...nothing else and not even that CPU that well.
Changing the FSB from 266 to 333 should be all there is to it from stock. It's when you start changing the voltages and pushing it higher that you really should consider a much better cooling solution than the stock HSF. Like some have said, air is fine, but its a person's own decision as to what is fine for them.
My only suggestion is to disable automatic voltage on the cpu in bios cause the mobo tends to overvolt a little when OC'ed. I have mine vdrop/droop modded and keep the setting well below the automatic setting. Less voltage, less heat.