My boss at work used to design bearings and stuff for automatic transmissions and knows everything there is to know about trannys and pretty much vehicles and engines. Today I asked him about engine / fuel treatments and cleaners to see if they actually work. He said that the cheap ones do nothing, but one that does work is the Techron one, it's around 10$ a bottle. He said anything with kerosene in it is pretty good. A crazy thing he said it that you can actually use ATF right in your gas tank and it will clean some stuff up and not hurt it.
I also mentioned SeaFoam and putting it in the vacuum line. He said he wasn't familiar with the stuff but said you could put injector cleaner in there too.

 

I use Auto RX for the crank case, and Redline SI-1 for the fuel system...

http://www.auto-rx.com/

http://www.redlineoil.com/products_f...bCategoryID=11