And as I said in the other thread EFI Live will also work for tuning your Trans Am for any modifications you make to it. On the Trans Am a Wide Band O2 sensor will be necessary to keep Air:Fuel ratios in check but on the Duramax you won't have to worry about A:F nearly as much and can do quite a bit of tweaking on the tune with no worries. As with Pat we give you a free tune with the purchase of EFI Live - ours is based off of what you have done to the truck, and what type of tune you want. On the stock turbo we can get you to 500hp and put you in the 12s but it's gonna need a built transmission and lift pump. Shimmed rail does not apply to your LB7. There are also EFI Live vendors and tuners that specialize in LS1 tuning that you can buy tunes for your TA from. I know of one that can get 40rwhp for your car with just a tune - he guarantees it. So while you will have all the capabilities of writing your own tunes you will not have to - there are plenty of resources out there for you to get proven tunes made specifically for your truck and car.
As was said the complete EFI Live setup, which includes 2 VIN licenses ready to tune your Trans Am and trucks runs $799.
A DSP5 switch is $50. We get ours through SoCal and sell them for the same price he does.
We have both in stock, ready to ship and can get you a DSP5 tune written with 5 tunes of your choice from stock up to 500hp (with the supporting mods listed in your other thread). You can call me at the number in my sig anytime from 8am to 9pm with any questions.