About to buy some powerheads, and I would like some advice for a 55g.

[Xyres]

So I am very new to the hobby and being only 20 cash it in short supply but dispite that I am putting a lot of money into this tank. It is a 55g that I am planning to have fish in, some corals and some anemones, the last two will be later on down the road. So with all that info my next question is this:

Would I be better off with one mp40 or two Tunze 6045? Is the different setting for the flow really that important? Is it worth spending the 300~ plus difference to get one pump? Any help would be greatly appreciated. Thanks!