My 08 SCAB 5.4 4x4 sure drives different than my 05 with exact same specs. The throttle response tho not nearly as good as GM or Toyota is still much better than the 05. I know the 05 had a reflash early on, did help some what but not at all like the 08. Could it be attributed to the stock exhaust vs after market? 05 had Magnaflow, sounded great not bad at speed, but I'm not sure bigger pipe and flow is good for low end response and torque. I always thought it helped more on the upper rpm range.