I have a 99 WR400 and have installed a new headpipe and exhaust from 2000 YZ426. I noticed good power increase from stock system but think the bike is just a little loud. Does anyone have an idea how the White Bros E Series S bend would compare relative to power/noise output. I will probably sell the 426 system and get a replacement with less noise since I have the baja design kit and get on public roads occasionally... 99WR, 1 size larger on pilot and main, snorkel removed and 2 1/8 out on air screw. Any advice is appreciated.