WRX drives very different from Legacy GT, even if Subaru puts the same engine on both of them. 2006 WRX will come with 2.5L turbo for North America and it is just a matter of time. Like the base wagon, It used to be 2.0L and now it is 2.5L. North American consumer is power hungry. Subaru can keep it the same 2L engine and boost the power. But, there would be turbo lag. So, the quick fix would be by increasing the size of engine. cheers.