I don't know about this Asian K90. I had a chance to hit indoors tonight with my 4.0-4.5 crew and my backhand was a mess. Volleying was pretty sweet with the lighter weight, which that is why I wanted it in the first place. It's great for those pick up balls close to the service line, but the smokers from the baseline are lacking. I still haven't put my usually full gut job in it yet so hopefully this will help, currently there's a gut/poly hybrid (how it came from kbui). I wanted to know if anyone has used both of these (US and Asian versions) extensively (I know allot of you have). What were your takes and which one did you end up with and why. And the one you liked more what custom weight mods did you make if any. And mind you I'm a 4.0 and don't need a 13+ oz racquet to absorb 110+ mph serves all day. Thanks y'all.