I used them on the K04'd mk5 when I ran my DM tune. They are fine without mods...but oem shouldn't give you troubles either. Mostly the NGK PFR7B @ 0.028" are used when high PSI results in unexplained misfires and usually fixes them. I didn't need them with the K04 running the GIAC High Output file...but when I tried a DM tune running @ 26 PSI...misfires and those plugs worked. Now, back to running GIAC file, I'm back to using the oem plugs without issue.