Welcome to the forum, glad you joined us
Yes the chain can make a lot of noise, is it adjusted correctly? Here is a link to help adjust the chain..http://motorbicycling.com/f3/replace...hain-1139.html
Losses power at the top of a hill? How big is this hill? What size rear sprocket are you using?
As far as the computer the electrical system on these motor's can affect the computer. Twist the wires from the motor and keep the computer wire as far away as possible. Or you could use shielding for the wires, I use wire loom.