Jeff Rowland to what?

I personally don't feel that you can improve on a new current-production JRDG amplifier for under $20K.  If you get a tube amp or a tube-hybrid amp you "might" get a result you like better, but for pure SS i don't see much real improvement in the way of refined sound or build quality.  
      If you want a significant improvement in most areas it's time for
a VERY good pair of speakers.  A 20x26 room (damped? undamped?)
is really quite a lot of space to deal with as well.
     I am a snob when it comes to evaluating listening material- classical music is SO much better recorded on average than anything else IMO
(acoustic folk and female vocals usually qualify as well). So,
IF your stereo system sounds good on Beethoven then count your blessings.  If your preference goes to pop music, "cool jazz", hard rock, etc. then fussy components like Rowland tend to sound a little "off".  In my book that's an acceptable trade-off.  

Hello ricred1,  I didn't want to imply that your speakers are inferior in some way- I have never heard them.  But one example i can offer is the day i heard Wilson MAXX
speakers and then after those the Alexandria's at a local store.  The upgrade was like
an entirely different way of experiencing the music.  Both speakers cost
a huge amount of money, but I couldn't even consider buying the MAXX's after hearing their flagship model.  In my own home i upgraded
from B&W-801s3 to Eggleston Andra's (and then to Andra-II's)- really no words can describe the improvement or the enjoyment i got from listening for hours on end.  I gave up the Egg's for Von Schweikert speakers and gained much more midrange clarity.  
    So i took a different path from you, and since there are no Monitor Audio dealers around town the issue never came up. I am also a huge fan of Sonus Faber's (a friend has a pair of Extrema's which sound out of this world).  
      You could improve your source components and/or your cables as well, but looking for a "better" amplifier than Rowland is IMO is going to be difficult. Plus you have the Corus preamp as well, so as one dealer told me when i purchased a Rowland Consonance w/phono a number of years ago, "you're done"- i.e.- go improve some other piece of gear.
Even today, that is one hell of a great preamp.