i have just written a hub on my experience on using the e3 spark plugs. If you are interested to see how i saved during this period of high fuel costs, check out this hub at <snipped link- please do not post for the sole purpose of promoting your hubs>

I would also recommend the Bosch Platinum tipped plugs and NGK has the NEW Titanium plugs that I put in my snowmobile and they run awesome! Just remember that tuneups will always help, but it is hard to believe that much of an increase for just adding spiffy plugs!

Tom