I know it doesn't really address your question, but I tow a 4,200# Jeep using a Blue Ox tow bar and base plate. I use the Roadmaster Invisibrake and love it. Permanently installs under the driver's seat, completely out of view. Works great and you never know it's there. Also, it's about $100 cheaper than the "sit it in the floor" types that you have to find a place to store when they're not in use. Don't know much about Autostop, but I'm a bit put back by a mechanical device trying to do this job rather than an electrical device. Just another engineer's opinion.
2015 Legacy SR340 360RB
2014 Jeep Wrangler Unlimited Toad
Gigi, Poppy and Sadie Lady...On the road, but not full time!