Is the delay at low rpm (like <2500)? A good tune down the track will help with power delivery.
It's had 58k km to develop a leak so certainly possible. Could be coils- usually them getting wet. Maybe the car was pressure washed before sale? You could pull them and check when you do the plugs. Apparently you can test them with a multimeter too.
You could also check the ground cables. The one at the hpfp is known to kill the engine if it disconnects. It might be loose and sporadically disconnecting.
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