Hi ByronT,
I suspect that if you ordered that 5-pack of parts off of ebay, it would most likely work out, but it’s always a bit of a risk there. However, if you want to try to use a TDA2030AV in its place, you would want to compare the circuits between the two and make a custom board with the TDA2030AV and all of the extra parts it needs and then run wires to the main circuit board from the appropriate points on your custom board.
I assume you’ve found a datasheet for the LA4425A-E online somewhere. I presume your board has it wired in similarly to the example circuit provided on page 2 of that datasheet, which looks like this:
LA4425A-E sample circuit:
Note that there are only 3 external caps and the speaker around the part.
Single supply schematic for the TDA2030AV from page 4 of the datasheet:
I have circled all of the parts you’ll need to add on your custom board to allow it to work in the same circuit board. The non-circled parts are presumably already on your board.
After you make your custom circuit board as shown, you’ll want to run wires from your board to the main board. I have shown where you would connect between the custom board and the main board below using green “wires”.
Additionally, you’ll likely need a heatsink to adequately cool the TDA2030A.