I have the stock WR headpipe with a YZ muffler on my WR, many of you have said the YZ muffler makes as much or more power compared to the after market ones available from WB or FMF etc. which is what prompted me to buy it. my question is does the stock WR header outperform the options as well or would a tapered header with a YZ muffler provide better all around performance? Anyone have any dyno proof to back up claims? Thanks!