I've got my defi boost, water and oil temp gauges installed this week and just fitted the turbotech boost controller to up the boost a bit. It now hits about 15 psi, and has increased the midrange power nicely. It was already hitting around 11psi before but not holding it for long. Boost cut seems to be around 17psi. The vr4 feels like a real turbo car now with a nice whack of torque in the mid range, just what you want for overtaking in 4th and 5th gear.