Is it huge improvement upgrade from KEF X300A wireless to KEF LS50 wireless?

[Dikey]

I've owned KEF X300A wireless for 6 years, and recently want to upgrade my KEF to KEF LS50 wireless. 

 

I send a email to KEF China, and they say there's no place for listenning LS50 wireless in my lived city (Hangzhou), they only sell them.

 

My question is, is it huge improvement upgrade from KEF X300A wireless to KEF LS50 wireless? It worth ?

 

And another option is B&W formation duo, but it's too expansive...