I have a 2000 ex cab shortbed 5.3 auto and I had Jason do a mail order tune... remove rear 02's, speed limiter, EGR up the shitft points and also work his magic with the torque managment too and wow what a difference def. will worth the money spent made a drastic difference in the performace aspect not to mention they made a 40hp difference tuning my LS1 camaro so just a suggestion to all who own a gen 3 motor truck this is a great mod for the money and it pulls to 130+ on the big end