1) Is the NGK BKR5EIX-11 the correct plug for my 2004 Crossfire? It is listed for the 2004 SLK320, nobody has listings for the Crossfire (I have had fantastic service from these NGK Iridium's in a 2-stroke dirtbike).

2) Assuming that this is the correct model plug, what about the heat range? The "5" heat range is what is called for as stock on the SLK320 everywhere I look except Needswings lists one step colder at "6" as the correct stock range and offers "7" as one step colder. What do you all use on stock daily driver cars?

Thanks in advance for the help, I tried the "search" here, and read a lot of threads, but I could not find the answers i needed.

 

yes that is the correct model number if your looking for the NGK Iridium IX Plugs...i have used them and had great results with these...the whole number is NGK #5464 BKR5EIX-11 but i went one step colder so you can get the "6" heat range if you want, dont forget to get 12 of them...it's recommended gap is .044" but i went with .039" with a torque of 21 ft/lbs.

 

xfireon20z, Thanks for the help.

Note: Northern California has a chain of Napa auto parts stores names "Riebe's". They have the NGK Iridium plugs on sale right now for $5.79 each. It may be the same at other Napa retailers, but I do not know.

 

the 5 heat range is incorrect, the stock range is 6, the 7 range is one step colder, a 5 plug would be 1 range hotter.