the best stuff comes from www.dangerden.com. Their blocks outperform everything else and are of the finest quality. They have a movie of one of their blocks performing up to 1400psi. Their cube radiator is second to none. Just add a danner or an eheim pump and you have an incredible setup. If you don't want to splurge the money for DD, then the Aquastealth II kit is pretty good.
What kit at overclockershidout are you finding to be $75, their cheapest runs about $100 and even that isnt that great specially when you are mixing aluminum with copper. The best deal, if you are looking for efficiency with price, is over at aquastealth.com. Right now you can get dual radiators (with copper tubing) for $20 and the pump, resoivor, and tubing for $16. Not bad, that basically is the whole kit for $36. All you need is a block and fans. You can get fans basically anywhere. The block; however, depends on your system, you may want to go to dangerden if you want the maze 2 but to save on shipping if you were going to go with maze 1, the jagged edge over at aquastealth.com would work in its place. Best of luck to your cooling!
depends on what a regular HSF is, but probably yes, Unless you are facing the Glaciator or Swifttech 462 you should be doing better. I would urge you to look at dangerden though, the extra money is worth it.