I believe HP Tuners can flash the tcm on most GM vehicles.
The HP Tuners MPVI3 (the hardware) is $400 bucks, and at least 2 universal credits are required at $50 bucks per credit..... so best case scenario it will cost a minimum of $500 for you to buy HP Tuners and re-flash it yourself.
HP Tuners charges for their hardware, and you must also buy credits to flash a vehicle. However, the software that runs on your computer to view and edit the tune file is free. When you purchase universal credits, they can be used on any vehicle.... but once they are "claimed" or registered with one certain vehicle, they can only be used on THAT vehicle. You can now flash and reflash THAT vehicle as many times as you like, forever.
Disclaimer: I am brand new to using HP Tuners myself so please do not take anything I said above as 100% fact. Please do your own research and verify everything for yourself before buying anything.
I do not believe anything like Forscan exists for GM vehicles. I've used Forscan twice..... it's cheap and it's great, especially for the price. However, in my limited experience, Forscan can NOT do everything. I needed to change the rear gear ratio in the computer and Forscan could not do it on the 2008 Crown Vic. It did allow me to disable the TPMS light on the dash, and enable the factory keyless entry..... but no-go on the rear gear ratio.