I have a 04' Busa and have done the following add ons: Full Ti-Force exhaust, BMC street air filter, yellowbox speedo calibrator, Switchable TRE, and PCIII USB. I'm experiencing heisitation/stumbling/sputtering between 3500 and 4100 in the lower gears. It's not noticable if you just rev right through it, but if I'm going throught city traffic and try to hold the revs in that range in the lower gears I get the stalling. The TRE doesn't help, and I even had it tuned on a dyno...which was a waist of money. Does anyone have a map or suggestions for this set up. I'm almost to the point of putting the stock exhaust backon.