I like the powerbomb design (esp. if I can still use the heat-shield) and if it can cut sound and give a little more bottom end, but the Ti factor is something to consider... If I can find a cheap YZ header maybe I'll give that a try first.
I thought the 08/09 YZ headers were larger diameter (due to restrictive endpipe/muffler)? I'm not sure I want to go too large and lose bottom end. Are YZ 06/07 same diameter? I've been digging around and can't find definitive answers - I wish someone could give measurements for each pipe.
Thanks for the cam advice. Would it be possible to modify the stock YZ decompression pin (anyway to re-use the WR pin?), or maybe use the hotcams exhaust and stock YZ intake? I thought WR's only had a different ex cam compared to the YZ, but I'm hearing both intake/exhaust are now different. Would just the exhaust or intake give them most improvement? I'll probably do both at once since I don't want to pull it apart 2x's.
Also, is a higher compression piston worthwhile (I don't want to run racegas). I mostly ride trails, but occasionally go to the dunes and desert so a little extra power would be nice.
I recently purchased this bike used, and it does ok, but I'm a little disappointed with the power, but I love the e-start and lights (I might try dual-sport someday). I have a friend with an 03 YZ450 - he says it's the most powerful YZ and they've been de-tuning them since, and after a short ride on a KTM 525, the WR feels like it's struggling. The previous owner had someone do all the mods (AIS, airbox, slip-on pipe, jetting, accel pump) and he said the gray wire was left in, but I just checked and it's been disconnected so I'm looking for other mods to try. Back when the 03 WR450 first appeared, a friend did the YZ mods to it and it easily outran a 03 CRF450, so I know there's some potential...