Is there Really a difference between a Krell 400xi intergrated amp and the newer Vandgard?


I currently own a Krell 400xi intergrated amp. It has 200 watts a 750k toroidal, balanced inputs, etc. Its very similar to the current vanguard intergrated amp in terms of similar spec's. I would like to know if anyone upgraded and if it was worth it? Is the sound different does it go lower, deeper, more of an open sound stage or should I just consider another route to improve what I already have.

thanks,

matt00
Does the digital module model have cast connections? , or maybe I can get my friends at krell to make a cast model for me. 
Really! , there is no tape loop or any thing like a tape loop on the vanguard when all past krell integrated's  had one,  I'm a huge krell fan, I  own krell now,  if the vanguard doesn't  have what's mentioned here,  than I may not be willing to use a vanguard,  to bad! 
I  believe I  will call my personal friend Patrick Bresnahan's personal cell phone and talk with him about this vanguard,  and see what modds are possible that can be done with the vanguard.