Hi!I have denon x6400, I bought it july 20 ,and now I 6500 came out with IMAX features, if I can change for the same price I'll definitely go for ,I got it from abt electronics, my question is what the diffrence between 6400 and 6500 besides IMAX thru firmware later on, price diffrence is 700$ ,6400 sells now for 1500 at crutchfield and abt has it to