HKS plugs compare to Stock Pics included
 

http://x1d.xanga.com/4cac56155943216...b127092253.jpg

From the left to the right : Boxes - HKS Trailing Plug - HKS Leading Plug - Stock Mazda 6 Heat Range Plugs - Stock Mazda 7 Heat Range Plugs

All made by NGK of course.

I think HKS plugs are made by NGK with HKS's specs.

From HKS site it said it *suppose* to be able to ignite better compare to stock plugs. and for the rest, I guess you guys know what they are.

according to HKS information.

their Leading plugs for Rx-8, M45REL heat range = NGK 9
Trailing plugs M55RET = NGK 11 !!!!

Meaning, they're MUCH colder plugs. Im not *sure* if its really *ok* to use them for now. Be brave and go ? :)

I am supposed to be receiving these plugs in the next couple of days. I will comment when I get them. Thanks for the info!

I got them almost 1/2 year ago but didnt change them out because I just change my plugs like maybe Jan or March last year.

If theres no rain today I will flush my coolant and see if I wanna change the plugs out.

I think the trailing plugs are a little cold for me. I may keep these around and install the NGKs at first. Once everything settles down with the turbo build then I may consider installing these. :dunno: