As long as you're only getting 2 (and you have no other labyrinth fish) you should be fine getting 2 dwarf gouramis. I have a pair in my 46 gallon bow tank and they get along pretty well. They have their terrorities and from time to time they do get grouchy and will chase each other, but it's never anything major. I tried adding more gouramis and it was a disaster, so I would definitely only recommend 2.,
75G- (3) Firemouth Cichlids, (10) Tiger Barbs, (3) Dojo Loaches, (3) Yoyo Loaches, and (1) Sailfin Pleco.
46G- (3) Pearl Gouramis, (5) Black Skirt Tetras, (7) Harlequin Rasboras, (3) Dojo Loaches, (1) Clown Pleco