vf34 is what came on the spec-c, vf30 is what comes on a normal version 7 motor. The two are identical. The vf34 has ball bearings, but the difference in spool is negligible.
Don't waste your time with a cobb stage 2. Only the exhaust will carry over. You can get motors with the turbo, intercooler etc for cheap, and it's the same as a cobb stage 2.
Honestly, just save. Get an exhaust if you want, but save save save. A JDM motor has all that you seem to want, no point in getting anything different that won't carry over. I wouldn't even bother with engine management, because it will change once you get the new motor.
Give a call to any of the vendors here, Kingpin, Gruppe-s, IAPerformance... ask for a price for everything that you want. I would also look into getting brakes and suspension. Get a price, and see how long it will take to save up.
ebeck is a guy on here who did it half assed. He went out and got a new turbo and such for his wrx motor, and then did the JDM swap later. He spent a lot more money than he should have, by his own admission.
So again, save for the JDM motor/tranny if you want etc. It will come with what you want. Get used to the power for a year or so, and then get a larger turbo. vf30 is only cool for a little while.