i have had a terror and blue acara together for about 8 months now and they are best buddies! from wot i gather it realy depends on the indervidual fish.
the blue acara's ive kept all got pushed around. and the GT i had was badass.
so keeping them together might be a bad idea. personaly i dont think blue acaras have much going for them.
besides the bit of blue on their face their more grey