A little bit of tuning can make the lower end components work just fine IF they aren't already.
I have a hunch, without more expertise fitting & adjusting components, any "upgrade" you do will just be a waste of money.

On my hybrid, since I only run "road" cassettes (12-23 typically) , I thought a "road" RDER might shift better. I switched in a Tiagara for an Acera. It's actually slightly worse. I seem to be having to "tweek" the barrel adj. 1/4-1/2 turn on a regular basis.