Refs: themommyvan, CharlieAnderson, bassknocker23, bigbirney420, wu501, _JaY_, lrc131, R/T Pimp, NeverEnuffBass, d-REW, slapmaster, headbussaboi, edzy, adio, 1ndatrunk, jfink, k_schutte, bigredhybrid, ARSkemp, s-saudio, pimpdaddyq, AudioFreak, scarolinablazin, ssackett, kylebechtold, craigzter, etc..................
It's the flares, the large smooth flares help lower the wind noise from the high velocity air movements. The only other thing is the finish inside the aeros, not that you couldn't do the same with a slot port, because you can.
Aeros are not necessarily better than slot ports.
My Current Build Log: (16 8" Sundown subwoofers)