A tune is eye opening if its done by someone who KNOWS what they are doing. Anytime you manipulate the conservative values in the factory tune, in an orchestrated way, will give you better performance, power, and mpg. If you can have Greg Banish do the tune you would understand immediately just by the feel in the seat of your pants! Mine had a 7 hr dyno tune done to it in LA before I bought it from a guy in Vegas; it had 347 HP 361 TQ to the rear wheels and thats with no other mods done or added. It was completely stock. Most SS's have just over 300HP to the rear wheels in stock tune and get to 335ish when tuned. How mine came out with more, I don't know but I have the dyno print out on it showing the results. When you can delve into HP Tuners for yourself and see the myriad of adjustable tables-fuel trims, spark, KR, shift points, TC lock up, torque management, etc then you might start to understand what gains there are to be made in a good tune. And with added bolt ons, a tune is necessary to take advantage of those add-ons.