Changing the entire chain gear mechanism
Addressing only the technical compatibility, if you currently have a Shimano 8x3 setup, and you wish to upgrade to another Shimano 8x3 setup, then any Shimano 8-speed road parts should be fine.

So that includes Claris, Sora, Tiagra etc. as long as it's 8-speed kit. Same goes for the chain.

I mention Sora and Tiagra just in case you're able to source these "old" parts at a decent price, off eBay or something.