Maybe you should try a Dodge truck. My Charger downshifts without me doing anything if idle throttle results in not enough braking force down a grade. It always holds the speed to +/- 1mph. It also has adaptive cruise - the one option I appreciate the most, times 10. It really shines on a rainy night, when the guy in front hits his brakes enough to light the brake lights but not enough to slow his speed. It doesn't slow down unless he really does slow down, and without it I'd be tapping my brakes whenever I see his light up. And it's collision warning has saved me once from a fender bender, or maybe worse. I can't say enough about the software in my Charger; everything it does is just what I'd want it to do.