as a plumber if you restrict intake .its less water moved but restict output it s a bigger blast of h2o same amount moved
like a finger over a hose...if you slow flow comming in it might over heat ...that amount might be needed for cooling
if i went to the 50 gal range ..id go 50 breeder cause of the width of the tank ...i agree a 55 would be really hard to scape..but good luck on your tank