I am an avid rider with about a dozen bikes. Last winter playing around I bought a mid drive bbs02 conversion kit from Luna Cycle and mounted it on one of my old 26" mountain bikes. I bought the 30 tooth sprocket and mounted it. I rode it some in the snow---what a mess---had a couple of great soft landings. Riding in the snow was kinda fun but is not going to be a regular event for me.
I do not like riding the bike with the 30 tooth sprocket around town. I am spun out at about 12-14 mph on flat ground without even using the power. I want a much higher gear than the 30 tooth for my 44 pound Ebike. I don't want to use the Steel Pie plate that came with the Bafang BBS02.
I bought the Lekkie 42 tooth aluminum sprocket for the BBS02. It is much better. Now without power I can work at pedaling. Without power it is slower than the bike was before the conversion because of the extra weight. At 44 pounds the bike is now heavy.
With power on I can easily cruise at 18-20. WOW.. 18-20 mph without working. I did a 15 mile evening cruise at 17-20 mph and I did not work at all.
You must upgrade to good disc brakes if you are adding the BBS02 to your bike. You will be able to ride uphill and on the flats at 20+ mph. You need much better braking. I added the 200mm BB7 Avid cable disc brake to the front of my bike and it works great. V-brakes on the front of your bike will not cut it with the added weight and speed you will get from your electric boost.
While my converted bike was quite comfortable for me to ride before the conversion I have added a suspension seatpost and a wider seat. It seems I am sitting harder on the seat with the ebike. Also with the extra speed my behind seems to take more of a beating.