Not the look of the motors... I honestly can care less what the motor looks like as it sits inside the box for me.. But say you take the HC design or even the XXX design the older ones... the Adire Brahma design xbl^2 motor... just from owning these... and running the newer stuff that is out now... I just keep wanting to go back to these older ones, they just sound better "to me" and seem to just out perform "AT Rated" completely better than most of everything I have ran that has came out in the last 3-5 years"ish" I know there is better subs but for when they was built to now, I just feel that everything should of been doubled as for performance, power handling, and so forth.. I have seen a lot of the older people that has been doing this for 20-30 years saying that the xbl^2 design is still one of the best designed motors out there... Like I said i'm not all that into the actual motor design and so forth which might be why i'm thinking nothing has been greatly improved upon.