Well its not ball bearing like the VF34, so off boost there is bugger all response. Also it has a larger exhaust housing than the VF35, better top end but at the expense of loss of low down torque.

And yes for a VF series Turbo, it will have some noticable Turbo lag. Compensated for by a wicked mid-range kick Old School Turbo Style.

Of course you can drive around the lack of response at low RPM. For Track work and Drags, the VF39 will be more than adequate. MC and Sprints, it will be a dog of a thing on a 2 litre EJ205 engine.

EJ257 engine, different story as that extra .5 litre makes more exhaust gases to spool up the Turbo quicker.

MY06/07 WRX owners can cheaply upgrade to 06/07 STi power by picking up a cheap VF30=VF43.

J