Converting pedal assist hardware


OK now for my second post! I am considering purchasing a 20" Green Bike GB-1 USA for my wife. My only concern is that this bike only has 3 levels of PAS and that the ramp up from one level to the next will be to dramatic. Can you get modification kits that allow me to take out the stock 3 level PAS and put in a 5 up to 9 level of PAS. Whats all involved in this kind of modification?
If this cant be done easily is there a way to customize each of the stock 3 levels of PAS that would feel comfortable for my wife or are those presets level set in stone and cant be altered. Hope this makes sense.
I am doing this right now. It's a lot of work and expense. It's easier for me because I am doing it on a bike I built.

To go from 3 level PAS, I have to change out the controller to one with 5 level. On your bike, you would have to find it and get one that fits in the same space. The connectors for the brakes, motor, battery, PAS sensor, throttle and console all have to be figured out. I know that info on my bike, but I did see where one connector had the wires flipped. It's also relatively expensive. I spent $100 on the upgrade. My motor only cost $120, and the old controller was $25.

I don't have any electrical problems, but I can't get the new LCD display mounted close to the grips where I can work the buttons, because it interferes with the left derailleur lever. I may have to shave the paddles.

So I don't recommend this as something to do on a brand new ebike. Enjoy it as it is. With 350W and 36 volts, you won;t likely see a wide disparity between PAS levels. The only thing that bothered me with 3 level PAS is that level 1 kicks the bike up quickly to 10 mph, which makes low speed pedal assist difficult. I did find that my new controller solves that problem. It works very well at low speeds.

If you are buying that bike off amazon, ask the seller if the controller just happens to have adjustments for PAS. Maybe it does.
I am hoping the 3 level PAS has internal adjustments for the level would think that would be standard on all PAS systems.
Replacing it seems like a real pita