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For what its worth the TDA2030 appears to be obsolete now, though some distributors still stock it.The TI LM675T and LM1875T parts have the same pin-out and are functionally very similar so should require minimal circuit changes.
The extra parts prevent high frequency oscillation. At extreme frequencies the inductance of the speaker means it doesn't load the circuit, and the IC needs load resistance to operate correctly.
The plugblock appears correct but the schematic shows the 12K resistor in the wrong place. It should connect between 8 and 7. The 100K resistor connects between 7 and 6.
FWIW the 250uF part prevents DC flowing through the speaker, as the IC output will be at half the supply voltage. It has to be at half supply so it can output AC waveforms.The 0.05uF and 10R network is needed to suppress instability (oscillation) at frequencies above the audio range. It isn't always needed but as the oscillation is difficult to diagnose it is safest to just fit them to be sure.