I remember when I used to do deliveries and before the subway construction, Keele St. south of Finch was a 60km/h zone. However the lanes were narrow, there was lots of traffic and unprotected turns, etc. Even if the road ahead was clear, you would rarely see vehicles going faster than 50km/h, and most would be doing 40km/h. Simply put, the conditions didn't feel safe to go much faster than the speed limit.
That said, we cannot rely on self-regulation to control our roads. There are many times and places it may seem safe to be going 130km/h+... until it is too late. Factor in infrequent driving tests (I'm not saying easy driving tests, as in recent decades it has gotten ridiculously difficult to acquire a full G license) to monitor and refresh one's skills, and I don't believe the population on a whole is ready for no or extremely high speed limits. While 130km/h-160km/h+ might be safe, the majority of people would not be responsible enough to drive at that speed. Increase it to 110km/h-120km/h in open suburban and rural locations, and provide a 10km/h grace before ticketing.
I would also lower the speed limit of the 401 collectors to 80-90km/h, due to the traffic volumes and the numerous lane changes involved (merging right from express to collectors to off ramps, merging left since in most cases the lanes eventually turn into off ramps.