Hi Jeff
There are so many ways to change the sound of your system, and everything affects everything else. I wouldn't jump into a preamp until I studied all the variables your system can give you by adding components. It's also important to do the apples vs apples thing. I'm sure everyone here means well, but are they listening the same way you are?
For example: someone recommending a preamp for you listening to their setup "far field" while your listening "near field" really doesn't tell you much. I'm an extreme near field listener myself in my current setup and some of the preamps suggested I wouldn't touch, because frankly they don't do so well when your near fielding it. Now you may be closer to a "mid field" listener than I am, but I would be careful as to not screwup your stage envelope.
All of these preamps are probably great setup a certain way, but for the near field listener, we tend to want to fall deeper into the stage (at least I do). So my suggestion when asking people stuff is to see where they are at as a listener. Huge difference between an against the wall listener and mid, near or extreme near.
good luck, just thought I would jump in since you mentioned position
Michael Green