Hi redwoodaudio
I could not agree with bdp24 more. Room treatments are often overlooked due mainly to the wife acceptance factor. Let's face it, most audiophiles don't have the luxury of a dedicated room. If you do, don't underestimate the benefit of room treatment. A word of caution, it's very easy to over do it. When done properly it can make the difference between good sounding system and a great system.
Placement of your speakers is absolutely critical. The difference of an 1/8" can also be the difference between good and great sound.
As far as tweaks are concerned regarding best bang for the buck, I think a good set of isolation feet can sound amazing (if you get good ones). I bought a set of the Critical Mass System Center Stage feet and couldn't believe the improvement. They are stupid expensive but boy do the work. In my opinion, they are worth every penny. I've tried just about all of them over the years with very different results. Some were good, some were just ok, some made it sound worse. You have to be careful. At first you think everything is better and then you remove them after a few weeks and you realize that it just made things sound different, not necessarily better. I had one set I thought were great and when I removed them and put the cd player back on just the shelf in the rack my tonal color came back. When they were under the cd player the tonality and timbre was gone! Caveat emptor. My advise is avoid coming to a quick conclusion. Take your time and listen carefully and then remove them and listen to the same material. The CMS feet really just blew me away. The new Wilson "Pedestal) feet are also supposed to be fantastic. Hope that helps. Take care.
Scot
