Most any cam you swap will trade power somewhere on the power curve- usually a low end power boosting cam will take from the top and vice versa.
Some of the early hotcams for the wr had issues- im pretty sure they have it corrected but it is a fact that some of the first wr hotcams had issues.
Most of your cams that make big power are top end cams and it is a fact that you will lose low end.
From all the research i have found the best off the shelf cam was made by wiseco (wci009) and is no longer in production. The 2nd best was the hotcams 4239 series cam. All of this was dyno proven by mbirt and mixxer on a yamaha atv forum- they tested pretty much every off the shelf 5 valve cam and of every one tested those two made the most hp of all.
For what its worth, through all the testing- exhaust cams made little to no difference in dyno numbers- it was mainly the intake cams that created power over the stock cams.
The 2006 yz cam set is pretty much identical in profile as the stage 1 (low end power building) hot cam.
Edited by knuckleduster271, July 30, 2016 - 07:29 PM.