Derek 2005 GTO
I did read several reviews before purchasing the programmer for my goat.Superchips is the best for my paticular application. Shift firmness is about like stock which is firm enough, shift points are great, right at where the LS2 powerband hits the maximum. I can tell that there is an increase in torque and hp because if it was not for traction control it would be hard to keep straight. When it hits second and third gears the backend is really trying to move around. Gas mileage is the same but I did not buy it for gas mileage. If you want to wake up your LS2 buy Superchips! Great product.
Fairly good bang for the $$$ 2004 Pontiac GTO
If you want a cheap way to add more power, the cortex is the way to go. I have an A4 "automatic" and it still breaks loose in 2nd gear. Spinning the tires at 40 mph. The gear changes are faster and more smooth, it adds a lot of torque. Overall a good value. The only downside is that there's not many options on there tune for add ons. The only thing the tune covers is a cold air intake. It doesn't have options for headers w/ high flow cats, or a catback system.