IMHO, I would be think twice about organics on a heavy GM fwd vehicle. They tranfer heat energy directly to the caliper piston and can boil the brake fluid without warning. This comes straight from the mouth of the Wagner sales rep that stopped by the little mom and pop parts store I used to run. He didn't want me to be liable in case someone lost their brakes, and I stopped selling organic pads after that. I also had one of my accounts tell me that they had a customer lose their brakes after replacing the pads with organics, the brake fluid boiled.

If it was my car I would look into new rotors and pads for the front, which does most of the braking anyways. It would take a while for new pads to seat on those old rotors, leading to longer stopping distances until they are broken in. Try these people for parts, they have awesome prices, and it's genuine GM parts: http://www.gmotors.com/

The brake rotors are a easy touch once the caliper is slid out of the way, they only add a beer or two to the whole job.