Whos running what? on what engine? Any noticable difffernence whether good or bad? I have an 01 a6 2.8 current owner put ngk irridium, seems to run great curious if i would get better performance with oem style plug.

 

Anyone on here will more than likely tell you that for the short 5000 miles they last, copper plugs are the way to go. Thing is most people don't want the expense of paying for new plugs at every oil change.
I personally have gone for Bosch+4 platinums. People seem to give them 2 thumbs up and there OE brand.
I have done some searching on here about this subject quite recently. The general consensus is that Bosch and NGK are great, Nippon are ok and avoid champion and autolite.
For performance, slightly over gapping copper plugs makes the most feelable difference.

 

buddy at dealer said bosch are best to!

 

A6 1998 Quattro - 179K

Bosch+4 platinum, my engine was running rough. installed these and it resolved the rough engine.