I didn't use seafoam spray, but threebond engine conditioner.
Same concept, spray through the throttle body, heatsoak it and wait 15 minutes and then start the engine.

Picture of my head intake side


That is the result but, this was taken after 15k KM after the treatment.
I guess the engine itself could been clean to start with or my driving style is rather agressive. (Lots of short burst accleration and high rev)

Just doing the seafoam spray or similar treatment.
I definetly felt a difference for cars that are high mileage (5 years or 100k KM and above)
Mine saga blm (135k KM when done), I felt FC a bit better. Rest felt the same, could be it that my engine was at it optimum to start with.
My friend neo (160k KM, when done), roughness at idle felt smoother but somehow the exhaust was a bit more alive.
Lastly, my friend myvi (130k KM, when done), sharper respond and better idling quality.

I would like to just do the seafoam in the engine and see how well does it contribute.
But it seem costly to do it; seafoam, engine oil for flushing, 2x proton oil filter and engine oil that i usually use which is molygen 5w-40.

like brand new. haha. remember is 155k KM and 15k KM after "decarbon"

for me the only that worries me, is seafoam adding to engine oil.
it can be added in petrol tank, before oil change and after oil change, and decarbonize valve and piston.
is a bit intriguting how one oil/additive/treament can do so much.
have you tried putting it after oil change?