Guitars, in general, do not sound better in the store than they do at your house. If you're playing it acoustically, meaning not plugged in, it won't sound any different in the store than it will sound in your house. If you plug it into a $2000 amp and then plug it into your $100 pignose at home, chances are very likely that it's going to sound different. Very different.
The AK P90 is not really made to sound twangy because of the very hot SD pickups. The same way that the mustang won't growl like the AK. You're really comparing apples to hamburgers. Construction is different, materials are different, etc...
Go tell Hamer, McNaught, Thorn, Driskill, Koll, Heatley, Baker, Robin, PRS, McInturff, etc that they are not interested in developping a better guitar and let me know what their reply is.
I don't know how to say this without coming off as rude, but man, you know how to take the fun out of this very cool hobby.