Can anyone get me started on my journey to get my wife into an E-bike. I rented a Rad and we liked it, but being a DYI-er, I realized there are components I could install myself. She has a Specialized step-through hybrid with 21 speeds. Will components give me the same usablity, safety, etc? Brand? Where to install the motor? How many watts needed for some local hill riding on pavement/fire roads? Thanks.