I've run both PP and Synpower (5W-20) in my V6 Accord with PureOnes and noticed a lot of noise when RPM's exceed 3K. The only other filter I run is Mobil 1 and there is no similar noise at this RPM level. Sounds very smooth. Only other variable is I've only run Mobil 1 oil (5W-20) with the Mobil 1 filter, but I don't think its the PP or Synpower. About 125K on the clock and she runs like the day I bought her. Anybody else noticed this and do you think its a problem?