I think I posted this links earlyer alredy here in the forum.

http://www.condensator.com/

http://www.agsint.com/cond.htm
http://www.eagle-research.com/fuelsav/ecarb.html
http://www.wyominginstruments.com/gas_home.htm
http://www.hydrogen-boost.com/tech-info.html

Most of them devices work on two principals.
1. Better vaporisation for better milage
2. Bring back unburned fuel to the engine

Both sounds good to me.

Has anyone experiance with this stuff or is it all Snake Oil Products?

This site sells no devices but was a real eye opener.
http://www.himacresearch.com/default.html

Frank