No biggie on the prices. Our fuel system uses a return setup so any unused fuel is sent back to the tank and recylced. The newer cars use a non return system and the fuel pump is controlled via the amount of voltage it sees (computer controlled) which determines how much fuel it pumps. You really cant say that the pump is overkill for the fact that the unused fuel is recylcled. There are those that argue that using a larger pump than needed will heat up the fuel. My outlook on this theory (its just a theory, no one has proven it) is that I would rather have the headroom and a bit more heat than risk running lean and possibly melting a piston (been there done that, thats a whole nother story though). The fact of the matter is that they believe the fuel is heated as it passes through the engine bay and dumped back in your tank (remember, at high pressure [about 40lbs and up] the fuel is travelling very quickly). In theory this causes you to make less HP overall (density vs volume issues). The truth of the matter is that most people let there tanks run below 1/4 which in turn means that there isnt enough fuel in the tank to keep the fuel pump submerged which in turn gets hot (the pump is cooled by the fuel) and the additional heat then heats up the fuel as it passes the pump which in turn has the same effect as their engine compartment theory. Bottom line here is its safer, more cost effective in the long run and simply easier to install the bigger pump.
BTW, while you are doing your installation, be sure to note the condition of the plug that attaches on top of the tank. Remove any corrosion you may find on the contacts and coat them in a corrosion resistant gel or other material (see radio shack for options). Poor contacts result in lower voltage and/or current to the fuel pump and that decreases your pumping capacity as well.
