I wanted to get my wife's car better consumption, she has a cayenne gts which drinks the stuff. Found out a company called de verde technologies and after a bit more homework bit the bullet and got all the cars done. Basically the idea is that he cells generate hydrogen which is fed directly into the air intake. A much cleaner burn and therefore more power as well. Wife's car is def a little better off and aero is as well I think but it's early days. Insurance company had no problem and there was no increase on the premiums. Not cheep tho at about £700 plus vat per car....
