Take a look at any production Class 3 (28mph) e-bike and then look at the same model (if any) sold without assist. For example: any Raleigh Redux (1 or 2) vs the Redux IE or the Giant Quick vs the Quck E+. The e-bike will have a (much) longer wheelbase. Hydraulic discs (180mm rotor f/r), 2.4" (vs (1.5") tires and usually integrates "be seen" lighting equipment. It will also cost a LOT more money than the unpowered version. Sure you can take whatever you've got and hotrod it with a motor kit but you might be missing out. I chose to try and get the best of both worlds. I didn't use an existing bike but I bought a new bike possessing most of the traits found on the best production e-bikes and then bought a mid-drive motor kit to power it. A short list of suitable donors include the Salsa Journeyman 650B Flatbar; Breezer Midtown; Surly Bridge Club. I couldn't find any of those bikes actually available! Everything is sold out. So I bought a Mongoose Envoy (large) and that was not easy to actually find. Someone returned one and I grabbed it. Ticks all the boxes. Tongshen TSDZ2 and 52V Battery from EM3EV round out the package. $4200 e-bike for $2000. Works for me. YMMV.