Hi Miro -
Even at top speeds my eplus is very smooth. There's no jerking, or sputtering. It's just complete silence, and a smooth ride.

BTW - for the top speed I am 225 lbs rolling down the road at 61 kmh (human + electric) so this Big Dummy/eplus are really working well.

One other thing I forgot to note, is that I also had the crankset replaced so I can pedal more effectively at higher speeds without spinning out. So my changes include:

1) Alex Rims DX32 - result = ride is much more solid underneath of me especially on bumps. As a result I feel like I can ride faster on the roads without getting tossed around by the bumps.

2) eplus lithium battery - result = range is doubled (because I also have the stock Nickel battery), and I feel more comfortable about dropping the hammer on the roads without thinking twice about conserving energy. It also "feels" like the lithium has slightly better acceleration and top speed. Not by much (maybe 2-3 mph), however, it's enough to tell a difference and set a preference in my mind. I'll use the lithium (for speed and acceleration) when I know my ride is going to entail ROADS where I need to go fast as opposed to bike paths where I need ride like a normal biker.

3) new crankset with 53 teeth - result = slightly better experience pedaling at top speeds VERSUS the factory crankset.

There are a few times when I wish I had the Tidal Force. Those times are mainly when I think about wanting to throw my ebike in the back of the car for an out of town trip (finding a car rack for the Big Dummy has been a pain), or take it on the metro, or carry it up to my office instead of locking it up downstairs. Overall though the Big Dummy/eplus has been a great experience.