Gonna agree with some and and offer some of my experience.
1) As above, first thing is to experiment with speaker placement. Definitely do this, take a couple of hours and test out different positions, separations etc to get a feel for how it changes things in your room.
2) Get hold of a Puritan PSM156 on demo or sale and return. Brilliant piece of kit. Will add clarity first, then image second in my experience. A reasonable priced bit of kit. Try out the ultimate power cable supplying it too if you can, although std cable is no slouch.
3) Ultimate upgrade for stereo image is Fo.Q TA-102 thick tape. Open up your source equipment and apply squares of it to the top of every cap you can find. An exceptionally cheap upgrade that will by far give you what you want. Given the budget you are considering, this will give you what you want almost for free. Try it, its on ebay or lotususa do it I think too (https://www.lotusgroupusa.com/foq.html)