the very first thing you will need to decide is where you are going to place your radiator, and how much space you have for it in that location. After that we will go about selecting a proper core for your case. Some people with full towers will remove both the lower front hard drive cages and use a dual 120mm rad, ie.. something around 10-12 inches in length. If you have a smaller space, like a mid tower or a full tower that you don't want to sacrifice the 2nd hdd cage a chevette core will do nice. they are about 7 1/4 i think in total length. Make sure you have that amount of clearance or more in the lower front of the case. If not, or you do not want it there for some reason, another effective way to mount the rad is to put it in the top of the case. See if you can take a look at the case you are using, or are going to be using, and see where everything will fit. Once you have determined where everything can fit we can go about figuring out mounting methods.
a word on mounting the pump,
as stated, this will greatly depend on what type of pump you will be using. A larger pump will have 4 mount holes in it's base. You can drill holes there and use rubber gromets and nylon bolts, this will cut down on vibration. Also double sided tape or some good strong velcro are other options.
*edit* no, you will not need to cut a hole for the T-line. Just keep the line where you can pull it out of the case a bit when the side panel is off.
J.