You'll definitely need to do your homework to make this work. I seem to recall some Grand Ams with AWD, and Pontiac 6000'* as well.
For the Versatrak, as I understand it, it'* intended to transfer power to the back in poor traction conditions. I don't know how robust the system is, but you'll need the transmission to go with it as well. Also keep in mind the most this system will have ever seen will be the 3400 V6, which is good for 170 HP, and not much more torque. Yes, the HD variant of the 4T65E has seen 240HP with an L67, and a lot more torque, but you stick a V8 in front of it, like a Gran Prix GXP engine, and it starts to hurt.
What is your final vision for the car, and what will you be doing with it?