Get an SSD for sure, and I would be careful with upgrading RAM. If you can it would be better if you bought 16GB of whole new RAM, from the same kit, since RAM tends to be very finicky, even with RAM of the same make and model, timings, and clock speed. RAM is put into kits for a reason, as those specific sticks are made to work together. It may not be the case with other RAM.
The rest of your build is fine and works well with each other.