Sora may be low end but it works fine. What might not be is length of life of it but the time to replace parts is when they wear out. Replace the rear derailler with any other you want as the R.D is not number of gear specific. May be some exceptions but a 10 speed shimano RD will replace any other shimano RD.
Front Derailler though and you will have trouble wearing it out. And some of these are gear specific. Double or triple chainrings and width of chain affect these.
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How long was I in the army? Five foot seven.
Spike Milligan