Biggredd2069

So I'm doing some research to do my first ebike conversion. I'm hoping the person I'm contacting will accept my offer on a Rain city Redline chopper bicycle. Has a fatty back tire. Thinking about doing a 48v 500 watt direct drive set up (maybe a 750 overdriven if I find a good price). My daily use will be 90% battery driven and 10% pedal. I just want to keep it pedal driven so I can go on bike paths and such. I'm 6'2", 200 pounds which is why I'm going for the bigger set up and want to at least be able to maintain 20mph on most all of the adventures I go on (or faster for fun). I plan to get some little motorcycle looking saddle bags to put the batteries in (fashion and function lol). My main question is when I'm searching for a kit to buy I see most are offering a new rim. Is there something special I need to look for to keep the stock tire or does that require some special modification? Also, this bike is belt driven - not chain. Will that be an issue or will I need to convert it? The bike is a limited edition so I don't mind doing some mods to it but don't wanna completely destroy it unless I have to.

EBikeFL 

Have you seen the bikes from https://www.voltagecycles.com? Check out their parts section.