as far as warranty goes the dealerships usually say it will block warranty for one of two reasons. one they have no idea to do what you are asking and two an aftermarket program will change warranty. Here is the beautiful thing about this the parts and program are gm. they cant say you messed up the bcm by installing their program. when the techline programs your car they write a new program to your vin. if and when you had a bcm go bad and got it replaced at any gm dealer when they went to replace and reprogram there wouldnt be an issue because it would reprogram for steering wheel controls without them doing anything it will already be part of your cars program from now on. with the bulletin i posted gm is admitting to letting you install this program. the reason warranty will not cover it and you have to pay for the program is because it is basically an accessory like a set of running boards on a truck or adding heated seat package supported by gm. you still have to pay for them and the install because there is nothing wrong with your vehicle. warranty issues are only covered if there is a defect or something wrong with your vehicle. the only thing wrong is that gm didnt offer this in the 1ss to begin with. hope that clears it up for you.
The Speed Demon (aka tech support)