My Colorado I5 did great with the E3. I have never had them in anything different

 

i tried two different plugs in my 2.4. i can honestly say there was no difference in performance or fuel economy in 3 different sets. one set was quite pricey and recommended on here somewhere

 

For some cars you can toss about anything in them and they will run. But there are other cars and some ignition systems that just work better with others.

Never have had the details as MFG just recomend what they put in and don't go into details. But once you get say a Honda with new Champions and you are told to put in the equal NGK and the runs fines you understand there is something to it.

Just never fall for the gimick trap and pay more for plugs that really do not add anything. Some offer snake oil in promises of power etc. Companies like Splitfire while they worked fine in many cars has to stop claims of power increase because it was not able to back up the claim.

There are other things you can better spend your money on.

The only real improvment you can do if the car did not come with them is upgrade to a better quality metal in the plug. It will improve power but it will improve life of the plug and wear. This in turn will improve performance over the long term.

I just hate leaving plugs in too long. I have had to fight too many plugs that would not come out of customers cars and feel better with a change every few years.

 

I have never been able to find a difference in plugs, since the mfgs have standardized the threads. Used to be in the dim, cold past some where threaded ASME and some metric; close enough most of the time, but...... .
Plugs difficult to remove, by any chance have to do with aluminum-alloy heads and steel-alloy plugs?