The tuning made a huge difference, I remember my 1/4 mile times without an ECU actually went backwards.

Not like the standard setup of the TD04 when you know the boost is going to be there at 2900rpm, with the VF34 it starts spooling in the low 3000rpm with full boost around 3400rpm. There is some element of lag with my setup (not much) but when you get use to driving the car within the rev range the boost is pretty much instant but saying that it's pretty much true for any turbo car. The tmic is the best for response but by design whereby it sits on top of a hot engine, I personally don't like that.