Spark plug Bosch or NGK

changed out some spark plugs, shop here: http://autotech.com/passat/b6-3-6l-2006-2009/3-6l-vr6-ngk-spark-plug.html also I decided to get a new valve cover (comes with new gasket, bolts, bolt o-rings, and of course a new PCV oil separator that are prone to fail)

I used NGK Iridium.

As for the spark plugs, both Bosch Iridium and NGK Laser Iridiums are fine, arguably even better than OEM (which are made by Denso, btw).

I have a 12 GLI with 82k and just changed my plugs for the first time. Holy cow what a difference. It had been running a little rough and even made it seem like the clutch was slipping on hard acceleration between 3 and 4. I thought it was carbon buildup, but I just had that cleaned up at 60k. The new plugs make it run like new again.

I either use Delco or NGK. Never had a problem with either of them.

OEM plugs are good but NGK iridiums are just as good and cheaper. If your car is stock, which if memory served correctly it is, then use NGK BKR8EIX.

I just bought my old APR S3+ '03 Jetta back. It's been running these for 12 years. I seem to be fine w/ my AEBs and my BKR7e plugs.

new NGK R's (copper) runs better but not 100%

The NGK's listed have a colder heat range. Great in the summer, it will misfire like crazy in the winter

this summer I switched from oem to platinum bosch plugs and just recently took to dealer and had plugs changed as they said the platinum plugs in fsi engine will cause some fuel to not burn properly.