My JDM EZ30D is on it's way to me and of course I want to do plugs while it's out. I was thinking Denso or NGK platinum so I don't have to change them for quite a while? Any reason I should or shouldn't use platinum in the EZ30? NGK or Denso? or some other brand?

Edited October 2, 20214 yr by laegion

The stock NGK plugs for the H6 are like 100k iridiums.  I’ve never seen plug issues and pulled them at 100k and they look like new.  Run them.

replace idler snd serpentine pulley bearings now and every 60k or so check or replace them. 

my 03 had those 'double platinums' from the factory, easy 80K or more unless abused somehow (some say regular fuel is bad in that engine, I always ran premium)

iridiums probably fine - w'ever NGK or the manual says should be fine.

You might consider new valve cover gaskets. Don't overtorque the bolts.

Edited October 2, 20214 yr by 1 Lucky Texan

definitely go with the NGK - and whatever type the manual calls for

The stock OEM plugs are great!

 I love never thinking about them. Tune ups are a thing of the past!  Slight exaggeration. 

All the 100k H6 plugs I’ve pulled look awesome.  Besides coloration from use in a combustion chamber they barely show any wear after 100k. Can’t say that about EJ plugs.

EJ plugs I change all the time and they’re a first thought with any performance or misfire issues. Those 6s are awesome I ignore them until about 100k when I consider…maybe…some day…when it’s real convenient….changing them.

Ive seen countless Subaru 4s with misfires from plugs and wires.  I’ve never seen it once with the H6s. I’m sure it happens but it’s not common.

They’re pricey but as far as longevity and fewer plug change jobs, the stock plugs are awesome and worth way more than the premium price tag. 

Edited October 3, 20214 yr by idosubaru