I have heard that aftermarket plugs (non-oem) have tendency to "jump" out of the head and cause severe damage to the engine of the car. Is this a true claim? Is this user error? Is their anything to worry about with switching my plugs?

 

I never had a problem with NKG Iridium, 2 years using them.

 

I have never had a problem on two different Minis.

 

I've seen a few brands that tend to come loose more than others. That's why I stick with the NGK plugs. The biggest thing is that you need to make sure you torque them when you replace them. Most people just hand tighten or overtighten them and that's where later they have problems. Plus I've done a bunch of dyno testing and haven't found power in replacing the plugs.

 

One item of note,be sure to torque your plugs when engine is cold.
Steve

 

Just put in plugs while my engine was cold. NGK iridium. and it worked great! Glad that I upgraded to these. Great idle and good response.

 

I have a set of Bosch in my Advance Auto Parts shopping cart; anybody have any experience with them? They have a 5-year warranty, vs. the 3-year on NGK, and I can't help myself, I'd rather have a German name in my German car. Pulled the NGKs on my 05 Cooper, just rolled over 100k, and they don't look bad, but the car (bought in Jan. with about 98k) came with no service history, so I think I should drop in a new set, plus O2 sensor, as recommended.

 

No experience personally with the Bosch, but they have always made a stand up product. What plug from them are you planning to buy?

 

They are the Platinum +4 #4417, similar in design to the NGK iridium BKR6EIX that are in it. I was under the impression the NGKs are what the 05 Cooper came with, that's why I'm not sure if they have been done. $5.99 for the Bosch vs $6.99 for the NGK, so price is not a big issue. I've gotten the impression that some shops are charging some pretty outrageous prices for these.

 

Excellent plug all things considered. I went with a single prong electrode plug this time around just to see if my response was any better, and it was mildly noticeable. But then again, what isn't noticeable on a justacooper? And you are absolutely right about some of the price gouging that occurs when it comes to aftermarket plugs.

 

I use NGK iridium, like everybody says, make sure you torque them and no problems should occur.

 

So far the plugs are fine. I felt the improvement over the old OEM plugs for sure. I good mod for cheap, just keep them in check and all should be fine