Maz65, a few random opinions:
the Magneplanar, DeVore and JBL are all excellent loudspeakers, but being that you have severe placement restrictions, how will any of these speakers sound better than what you already have? From looking at your system pic it appears one speaker has to be in a corner and the other speaker is next to an open area. Both speakers look like they are fairly close to the rear wall. Most full range loudspeakers will have problems in the lower midrange thru bass with your arrangement. That's why I earlier suggested the bass equalizer. Additionally, the Maggies and the DeVores will not go lower in the bass than the Spendors. Someone suggested Gradient Revolutions -- I have these speakers and they don't have the midrange of the Spendors and they are very inefficient (you'll need a new amp). The Gradients have better placement flexibility, a more linear bass and far outclass the Spendor in soundstage/imaging. Basically, if you switch to any of the speakers mentioned I think you could lose the things you like about the Spendors without really gaining the improvements in the bass you desire.
the Magneplanar, DeVore and JBL are all excellent loudspeakers, but being that you have severe placement restrictions, how will any of these speakers sound better than what you already have? From looking at your system pic it appears one speaker has to be in a corner and the other speaker is next to an open area. Both speakers look like they are fairly close to the rear wall. Most full range loudspeakers will have problems in the lower midrange thru bass with your arrangement. That's why I earlier suggested the bass equalizer. Additionally, the Maggies and the DeVores will not go lower in the bass than the Spendors. Someone suggested Gradient Revolutions -- I have these speakers and they don't have the midrange of the Spendors and they are very inefficient (you'll need a new amp). The Gradients have better placement flexibility, a more linear bass and far outclass the Spendor in soundstage/imaging. Basically, if you switch to any of the speakers mentioned I think you could lose the things you like about the Spendors without really gaining the improvements in the bass you desire.