VagabondJ, I think you are possibly looking in the wrong direction for sound improvement. Your amp is what I suspect is the problem, and (if set up properly) you have a good source. Your Grandes should have everything you need, especially in your small listening room.
Case in point #1: I ran a Canadian made Ideal Innovations Elite 80 20 watt per channel 6AV5 PP tube amp with Omega 4-1/2" 93db Super 5 Monitors on 24" stands and the other listener kept asking "is the sub on?" It wasn't. This combo has incredible speed, super clear top end, and lovely bass, not to mention a large and focused soundstage. Next step up from this is the Super 5 XRS tower - just a killer speaker with same sound but more bass.
I believe your amp is 38 watts per channel, and it should make your Grandes just sing. However, rated power is not everything, its the quality of that power, and how well it is matched to your speakers that is everything. You may have a great amp but it may not be a good match for your speakers. Try some different amps if you can.
Case in point #2: Another combo that absolutely pulls me into the music is the 2 watt per channel Decware SE84 Select SET with V-Caps and stepped attenuator running the 97db Hoyt Bedford Type 1 speakers on 18" Lovan Jazz stands. This system has the biggest, most etherial sound stage I have ever heard, and a sub is not necessary. I have never in my long audio history heard such effortless sound. The system just gets completely out of the way.
Lastly, what kind of music do you favour?