I did the seafoam in the oil thing. I used it in conjunction with advice from here to pull the plug with the engine hot and let it drain overnight.

I think that frequent oil changes are all that is really necessary in this area.

But I am not one of those people who "feels" a 10% increase in power after I change the oil.

I filled my fuel filter with seafoam once when I changed the filter. I think that learning to break down your injectors and clean them is all that is necessary in that area.

Seafoam is ok but don't expect too much. There is only one real escape from the physical world.