Just a little food for thought.
A guy posted on bookface about his slingshot going full throttle when he was coming to a stop with the clutch in. He shut the key off right away and it was okay when he restarted. A few blocks down the road it went full throttle again while he was shifting gears. Found out a day later he had the pedalmax installed the weekend before.
This is the only rev issue I've read about, but damn..
Some people with the Pedal Commander on their trucks had the same issue which is a real bummer, as I was contemplating it for my truck. It is a small percentage of owners, but risk reward takes a big hit in my book.
It would be less dangerous in a manual as you can press in the clutch. None the less annoying and inconvenient.
When working properly, many, many people love them(according to reviews).