Chinese TPA3251 amp upgrade

So, I have bought a cheap chinese amp XY-S350H with TPA3251D2.

My question is which parts I should upgrade in this amp to make it sound better? (I can solder SMD parts too)
I'm pretty sure I should change this cheap capacitors, but can't decide which I should use and what else I can upgrade.

There is some detailed photos so you can check it:

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So changing this capacitors to some audio grade ones won't improve anything? About damaging something, I'm not worried, I can solder SMD parts easily, I'm working with microcontrollers and replaced for example ATMEGA2560 many times, so that's not a problem for me. I'm just newbie in Audio design as it is my first amplifier
No. "Better" capacitors are for audiophile grade equipment with ppm THD, not a class-D Chinese amplifier, and the actual difference is debatable, generally unmeasurable. But cheap stuff often uses caps that are as small as they can get away with, so if you want any bass, you need to calculate the frequency they roll off at and upgrade those that are going to kill the bass. You need the schematic. But cheap capacitors are notorious for premature failure, especially electrolytic capacitors, so reliability is your problem, not sound quality. Having said that, I have seen cheap stuff that had design mistakes, bad ideas, but there you need to know the amp well enough to redesign it. "Bolt-on" upgrades are not going to fix such issues.
“Bigger” heat sink wont help anything without a fan. The problem isn’t the size, it’s the orientation. Laying flat it will NOT convection cool. That’s why forced air is needed.

Fatal flaw for this SMD garbage. No way to cool them without fans. Unless you put a real heat sink on it and then stand the stupid PCB on end to run the fins so hot air naturally rises through it.