Review on NGK 94124 ILKAR7L11 Laser Iridium Spark Plug 4-Pack: Reliable Performance at its Finest by Christian Byrd

modified spark plugs Mazda 6 2014 for 90k in addition. It definitely runs smoother and I really think it helped reduce my gas mileage by 1-2mpg. Clearance was identical to OE spark plugs when checked with precision feeler gauges. Should have been changed at 70,000 as suggested in the owner's manual. My dealer didn't even mention it. I used this socket https://www.amazon.com/gp/product/B071W7XZZ4/ref=oh_aui_detailpage_o07_s00?ie=UTF8&psc=1. If you have a 14mm deep head to break them in, I've found that the 5/8 spark plug head removes it as soon as you unscrew it all the way, so you can probably get by without the head if you're patient. I was also able to put them back in by using the rubber in the 5/8 socket to start the thread and then tightening them down to 14mm.