170w isn't going to move a rider on a 40 or 50 lb e bike up any of the hills where I live (Bay Area). I had a dedicated 250w a few years ago - and it always ran the risk of overheating on even short hill climbs. It kills the bike to grind slowly on an ebike from what I've read, you want to be in the top % of power. And while I personally don't see any need for anything over 20mph, I don't think restricting them because of insufficient rider skill is valid. We let anyone with a basic drivers license drive a Porsche and other cars which can go well over 100 mph - there's no restriction - and it takes a LOT of skill to control a car at that kind of speed. I mean, since the posted speed limits in every state max out at 70 (more or less) why even make cars that can go 130mph? Considering there is less risk of hurting others with an e-bike than a speeding car, I just don't see the justification.