Well this is definitly one of those "for the hell of it" mods. Im only did this since I was installing headers(thanks Dan!) and Perrin inlet today, and I knew a guy selling a brand new VF34 that once I sell my deadbolt'd VF39 will hopefully be a free swap.
No mention has been made of using a VF34 since everyone just assumed use a VF22 being the biggest VF, but the 34 is actually bigger than our 39(P18 turbine vs. P17 and 30/34 has larger compressor as well) and with its more efficient design I should avoid the lag STi guys are still getting with the 22s, also since WRX guys use the 30/34 with our size injectors I should be just fine at stock boost levels. I'll dyno this setup in a few days, Im not looking for tons of extra power, just want what all of us want, a turbo that can hold boost to redline without going with bigger injectors and engine managment, I'll post results!