I haven't done these to my SVXi. They sound fine and idle smooth.
Perhaps I don't need to do that, and I don't plan to.
While my mazda V6 was at 100K, I did "seafoam" once to that car.
Before the oil change, I poured into 1/3 into engine and also drove
around 10 miles. I was really surprised that it didn't really smoke much
at all or crazy like the Impreza above in YouTube.
Maybe my car engine was really clean inside.
I always got consistent
mpg on that engine and it idled very quiet.
If you always take care of your engine and oil change at good
interval, use good quality engine oil such as Mobil 1 and etc, you
probably don't need to do "seafoam".
