I have a 3.5 on there now and I only see knock at wot between the 1/2 shift and it's only a 1.something, nothing major. I am looking to put on the 3.3 when the smaller belt arrives. I have done some reading and I see comments all over for yes or no. I have sd headers, 160 thermostat, cai and a gen v. I have hptuners for logging but I only use it when getting a log for my tuner. I also have an ultra guage (http://www.ultra-gauge.com/ultragauge/) that I have hooked up all the time.
EDiT, I also have 3" exhaust, tr55's
