My does 35mph and I'd really like to get it up to 45mph (70kph), because I really only feel safe in traffic when I'm matching their speed. In combination with the speed increase, I must add better braking which is already inadequate at 35mph. My plan is to add plug braking (eventually regen), along with a brake light and turn signal. At the same time I'm making a lower more rearward and far more comfortable saddle that will be somewhere between a motorcycle type seat and the old banana seat I had on my bike as a kid.
I'm not after more speed for the thrill of it, just to match traffic speeds better. For thrills in the form of a big boost in acceleration, and to reduce motor heat while hill climbing, I'm adding a geared rear hub whose assist will top out at about 30mph. I've had motorcycles and sports cars and always found thrill in great acceleration more than in high speed, and I just want my ebike to leave all the little gas scooters and small motorcycles that weave to the front at stoplights eating my silent in silence, maybe sometimes throw in some leisurely pedaling to fool them. I feel that's the best role I can play in making EV's popular, which are currently non-existent in this country.
John