It's funny how everyone refuses to change gears when over taking then all of a sudden says the set up is laggy. Driving my hsv 6.0l auto daily for 6 years, with all that bottom end torque it still geared down when overtaking or pulling out quickly from traffic.... go figure, maybe the computer and converter got it wrong for all that time. Based on everyone's theories it must of been laggier than an rb26 with -9s because apparently you guys never change gears to overtake. My experience driving mine daily is that it remains off boost for 90 percent of the time and when - need to cut in or overtake, I hold my revs up wait for the right time and rape the road, no lag, not waiting for anything to happen just instant torque and power as soon as I need it, and we are talking 3500rpm up not holding it at 4500 rpm as some of you suggest you need to do with -5s, that opinion is garbage and false. If the op want quicker spool up rates and lower rpm max boost, he needs the suggested breathing mods and tell his tuner to tune it for response/ cam gear settings etc, as already suggested. And yes it will be a totally different car. If he wants a demonstration I am more than happy to show him with my exhaust valve closed where the turbos take an eternity to spool and with it open where it ramps up aggressively from 3500rpm. A pure and honest comparison of the 2 extremes of a choked up exhaust system compared to a high flowing exhaust system that change the car characteristics immensely.