Hi Tony

Water cooling kits they're OK,but really depends on yours needs,I prefer normal heatsink which is OK for my needs,water cooling I've previously installed older Corsair H50 which has been very noisy on full revs,due this I went with Thermalright CPU cooler 

Overclocking is  easy in nowdays and doesn't require too much to know and on Overclockers forum are several good guides and they're very detailed,on stock cooler I wouldn't do that,they're rubbish for that and they're very noisy

You can gain lots of performance with overclocking as I've,its worth to overclock if you are rendering a lot as most of the render SW are CPU based too

I would start with older PC which you don't need,but still most of the cases and motherboards comes with detailed instructions which only help

Hope this help there

Thanks,Jura