The Crucial MX500 SSD is a good choice as well. Plus Crucial memory is very good too. Just make sure to only purchase the exact memory part numbers identified by using one of the two tools on the Crucial website for identifying compatible memory. You cannot just go by memory speed as there are a lot of other timings which are critical for compatibility, but Apple does not list those other details. If you purchase Crucial memory from a third party, then make sure to only order the exact part numbers Crucial's website suggests. The memory you receive should say "Mac Compatible" or "For Mac" on the plastic packaging (the web page should also say this as well). Stay away from the Crucial BX500 SSD as it is just a low end budget economy model that can be as slow as a hard drive plus it tends to overheat during large data transfers. In addition the BX500 SSD has a high rate of failure.
If you have the 13" non-Retina model, then if there are any issues with the new SSD, then it may be due to the internal hard drive SATA Cable which has an extremely high rate of failure especially when using an SSD.
FYI, do you need the full 16GB of RAM? You can purchase just a single 8GB stick of RAM and keep using one of the original 4GB sticks of RAM for a total of 12GB. However, you may not even need this extra memory. Use the laptop normally especially with your heaviest workload over several days, then check the Memory tab of Activity Monitor. If the memory pressure graph is green and there are not GBs of Swap or Compressed Memory, then you do not need more memory. If the memory pressure is yellow, then maybe a bit more memory may help. If memory pressure is Red, then get the full memory upgrade.
The SSD will give you the biggest performance increase.
