I have a 2009 silverado 1500 XFE model 5.3 6 speed trans 3:08 gears 22 inch wheels.The truck is a crew cab 2 wheel drive.My only mods are cold air intake and magnaflow exhaust.i am new to this site and we have not plugged the hp tuner in yet . I really don't know where to begin to gain performance. My only issue with the truck know is I keep getting a P172,p175 code once in awhile after cold air intake install.