I don't normally go for the various engine cleaning aids, but with all the Sea Foam comments, I had to try it.
At 126k miles, I can't usually use 5th gear on the highway, it just loses speed and I have to drop back to 4th. Added Sea Foam to a tank of gas and drove her around town a bit, then took her on the highway. No major acceleration difference with the little 4-banger, but I put it in 5th and was able to hold speed! Major accomplishment. I was even able to accelerate somewhat in 5th gear, that was unheard of before!
I will give it a few tanks of gas, just to make sure the Sea Foam itself isn't adding to the hp, but I am definitely impressed!