Actualy im waiting for reviews also. Would like to know if they could lower TDP to rumored 150-160w and raise performance. 7870 is a 175w card.
Sounds like what you want is the R9 270 (non-X). Fully enabled Pitcairn, 150W TDP with one 6-pin connector.
The 300 series basically ignores TDP entirely, and pushes the chips' core clocks and memory controllers as hard as they can possibly go to eke out a few more FPS. Even if it was released in the US, R9 370X isn't going to do what you're looking for. It will probably cap out at 225W (two 6-pin or one 8-pin connectors).