These plugs definitely deliver on the fuel economy reports! using standard plugs i was getting 925kms per 60 litres of fuel between brisbane and sydney under exactly the same driving conditions using 98 octane fuel. With these i got just over 1000kms. Now that was impressive, and my car is a 2002 hyundai elantra :) with 240,000kms on the clock!i was going to wait till these plugs were due to reach thier maxiumum life expectancy (currently sitting at 80,000kms and no pinging, burnt or corroded plugs yet) but when i found that i could buy them on amazon and have them shipped here to australia for $21 less than what they are on the shelves per plug.. for peace of mind i'm going to change them early =Donce again, shopping online with amazon has saved me a bucket load! &lt;3, as of 28th april 2014, im still making money off these! read my edit!I love online shopping! Cant wipe the smile off my face haha!***EDIT 29/4/14****ive been claiming that i am getting an extra 75kms per tank on the highway per 60 litres (ive converted a few things to imperial) but another amazon user has claimed a 2 mile per gallon saving on fuel, so i worked this out using my car as an example,...and found i would get 42.9km extra, however i have definitely been getting a consistant 50+ kilometers after using these spark plugs, and im a statistics nutter, keeping records of fuel efficiency, and consumption when ever i install new parts as i enjoy investigating these things. when i input the figure of 42.9km into my cars highway fuel efficiency of 7.2 litres per 100km.. i save 5.95 litres of fuel with these plugs, or 1.31 gallons. 98 octane fuel here in australia is $1.65 average per litre, (i wish my fuel was cheap like the states!), so per 60 litres per week im saving $9.81.these plugs cost $7 ea, so i use 4 of them, $28. It will only take me 3 weeks of highway driving to recoup my costs, perhaps a few weeks more if you factor in the cost of shipping. Here is the best part. Then you start MAKING MONEY!! the lifespan of these plugs is at least 90,000kms, in 4 weeks i will do 4,000 kms of highway driving leaving another 86 weeks to go. 86 x $9.81 = $843.66 !!!!how could you complain with that? it is clearly a win win here folks!