From glancing at the reviews it looks like the pump can be removed. The guys at the store are just idiots.
The water cooling kit comes with compression fittings and they are probably the standard G 1/4 threaded which would be compatible with the vast majority of PC water cooling parts out there. Keep in mind you are likely going to need a new reservoir along with your new pump because the one your case uses is integrated with the pump and finding an exact replacement is sketchy. You will also need a refill of the coolant liquid/additive (distilled water and a water cooler safe additive are usually pretty inexpensive though) and quite often replacing parts like that will mean you will also be in the market for some new tubing because the existing tubing won't reach a new pump design or will kink or something.
So basically things you need to know before ordering a replacement pump:
What threading type/size your fittings are.
What size tubing do you currently have. (Thermaltake site indicates 3/8", if you need new fittings for the new pump, this would be the size you would look for.)
What type of coolant additives are you currently using.
As for which pumps to look at, Swiftech is a really popular brand: The MCP 655 is a favorite in the industry although because it is so powerful it is rather large, it is only really required when you have water blocks with internal jet designs that are more restrictive and require higher pressure/head. The MCP 350 and 355 are smaller but can generally tackle most cooling loops without issue.
In my own coolers I used the other popular brand: Eheim, I got mine before they even had 12v versions so it has to plug into 115v AC. It most closely resembles the Eheim HPPS series which are a little more powerful than mine (which is only rated for 80 GPH). However it still works despite being well over a decade old and having probably in excess of 100,000 hours of actual in operation time on it. These pumps don't have as much pressure or head as the MCP 655 from Swiftech, so they aren't as suitable for highly restrictive loops but they are very reliable and not many people have loops that are *that* restrictive.
Don't worry about the GPH/flow rate, it is generally nonsense and is the flow of the pump with no load on it. Just so you know the 300 GPH rating on the Swiftech 655 unloaded will produce a jet of water 3/8 inch thick that will reach about 15-20 feet away from the pump if you just opened the lines with the pump unloaded. Even at 90 GPH a pump will circulate the entire volume of water in most cooling loops in less than a second and that is taking in to account that even the least restrictive cooling loops will reduce the flow rate by 50% or more from the pumps maximum specification.
So now that all the infodump is done, here is a good site to shop for water cooling parts:
http://www.frozencpu.com/cat/l2/g30/c10 ... Pumps.html" onclick="window.open(this.href);return false;
