The differences in sound are not going to be much. Just get the one honestly you can find the best deal on. Your Fiio E11 amp will run the 32, 80 or the 250 ohm just fine. No need to purchase a new amp. Just find your best deal and pull the trigger and enjoy. DT770+E11 is a nice set up, but you never mentioned your source.... ipod? phone?.. what are you using?