What engine are you running? 4AC?, 4AGE? Big port? Small port? Other? Normally if your existing coil does not use a resistor your replacement coil would not need to have a resistor. I think that its usually Carb'd cars that run a resistor or one that still runs points, not entirely sure on this tho. From the link the GT40R is a canister type and if your existing one is also canister it should mount right in, just make sure you wire up the polarity properly. If you are running a small port your coil will not be of canister type but of the transformer type and to replace this you will need to cut off the plug at the coil and wire up the thicker wire to the "+" side of teh coil and the smaller thinner wire to the "-" side of the coil. You might want to look at the coils from MSD, apparently for oil-filled coils you are supposed to run them upright due to the oil inside as they may overheat but from what I have seen most of them from factory are run horizontally.
Hope this helps.
Cheers, David