MartinLoganMotion 8i Center Channel Speaker Single Speaker (Gloss Black)

what is the difference between the ML 8 and the 8i? thanks

Does this can be place vertical and horizotal ?

So, between the motion slm flat lcr, the 6i and the 8i, wich is the best talking just about sound and performance? besides price that seems the same

will this work with the rest of my 8 ohm surround speakers since this is 4 ohm ? or will it have less volume ? back of my reciever says 6 to 16 ohm.