I too read about the seafoam and decided to do my 2 vehicles - a 2001 Accord w/77k and a 97 Jeep Cherokee w/115K on it.
I saw no difference in either vehicle after the treatment but the Jeep suddenly displayed a check engine light after about 5 miles of driving. The code is Oxygen sensor. I wonder if the seafoam has a tendency to gunk up the sensors.