The real threat is if riders on 150s start winning, then there will be an outcry. The new issue of Dirt Bike (Aug 2010) has the 125 class of the WORCS series which is basically all 144s. They have some short articles on a TM144, 150SX, CR144, and YZ144. The fully modified 150 sounds like it is totally bada--! The CR is stroked, ported/ head mods, fully modified and according to the article is one mean bike. I feel pretty confident that in the hands of a pro these bikes will start winning SX an MX.